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298 Cards in this Set
- Front
- Back
parasympathetic neurons originate from
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midbrain, medulla oblongata or sacral region
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where do parasym nerves synaspe with post ganglionic neurons?
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typically close to the effector tissue
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parasym preganglionic neurons are
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long
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sympathetic preganglion neurons are ___. They originate from _______ spinal cord
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short; thoracolumbar
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sympathetic neurons synapse with post ganglionic neurons in:
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ganglia close to the spinal cord
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symp and parasymp systems typically work in
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opposition
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cholinergic neurons
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NT is Ach. Pregangl: symp and parasymp. Postgangl: parasymp only
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adrenergic neurons
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NT is NEpi. Post ganglionic: sympathic only
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what releases epinephrine
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adrenal medulla
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some adrenergic neurons release
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dopamine
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NANC neurotransmitter
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nitroc oxide
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muscarinic receptors are innervated by
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post ganglionic parasympathetic nerves
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nicotinic receptors are innervated by
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preganglionic sympathetic and parasympathetic nerves
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a adrenergic receptors are
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excitatory, except in GI
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b adrenergic receptors are
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inhibitory, except in heart
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dopamine1 receptors
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selective vasodilation of renal, mesenteric and coronary vessels
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SNS to the heart
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(b-1rc)increases rate, force, conduction velocity, automaticity
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ParaSNS to the heart
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(musc rc) decreases rate, force, conduction velocity
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SNS to GI
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(a-1 rc) smooth m relaxation, contracts sphincters, decrease secretion= overall inhibition
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ParaSNS to GI
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(musc rc) smooth m contractions, relaxes sphincters, secretions increasion.
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parasympathomimetics
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increase GI motility
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SNS to vasculature
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(a rc), generally vasoconstriction
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ParaSNS to vasculature
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(musc rc) generally vasodilation
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selective vasodilation (of renal, mesenteric and coronary vessels) NT=
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NO (by NANC) fibers
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SNS to sweat
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secretions increased. Horse = b adrenergic rc, non horse = sympathetic cholinergic/muscarinic
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role of parasympathetic in sweating?
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none
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SNS / salivation
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low volume, viscous
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ParaSNS / salivation
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high volume, dilute
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SNS to eye
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mydriasis, distance vision.
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ParaSNS to eye
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miosis, near vision
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radial m
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dilates pupil --> mydriasis. SNS
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constrictor m
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constricts pupil --> miosis ParaSNS
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Ciliary mm
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ParaSNS= Can lead to glaucoma (tx = anticholinergic, carbonic anhydrase inhibitor, prostaglandins). Also SNS- relaxation
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what does the ciliary mm control
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lens thickness( para=contract, symp=relax)
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define glaucoma
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increased intraocular pressure
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effect of muscarinic agonists on ciliary mm
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increase contraction and increase outflow
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effect of prostaglandins on glaucoma
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increase outflow through alternate pathway
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effect of carbonic anhydrase inhibitors on glaucoma
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decrase aqueous humor production
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SNS to urinary bladder
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relax bladder wall (beta3 rc), sphincter contracts (a1 rc)
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ParaSNS to urinary bladder
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bladder wall contracts (M3 rc) sphincter relaxes.
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what nerve carries paraSNS fibers to bladder wall
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pelvic n (detrussor m)
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what nerve carries SNS fibers to bladder wall
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hypogastric n
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urinary bladder somatic control is via _____ n. it _____ the sphincter
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pudendal; contracts
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NT for pelvic nerve
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ParasNS = ACh
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NT for hypogastric nerve
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SNS= NE
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NT for pudendal nerve
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somatic - ACh
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neurotransmitter for relaxation of urethral smooth m
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nitric oxide
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receptor type for contraction of urethral smooth m
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a1 receptor
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there is ____ innervation to sweat glands but no _____
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sympathetic ; parasympathetic
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postganglionic fiber to sweat glands releases _____ and activates _____ rc to increase sweating.
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acetylcholine; muscarinic
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the horse has ______ sympathetic fibers that activate ___ receptor to increase sweating
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adrenergic ; beta
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the SNS and paraSNS work in _____ and ____ fashion to regulate organ systems
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coordianted and opposing
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cholinergic neurons release
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ACh
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adrenergic neurons release
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NEpi
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autonomic drugs are most intesively used in
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cardiology, anesthesiology, emergency/crit care medicine
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how do drugs work in the autonomic nervous system?
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generally either activate or block neurotransmitter receptors
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an agonist will
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activate receptor, therefore increasing signalling through that receptor
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an agonist mimics the
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endogenous signal.
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ACh relaesed by vagus n at sinoatrial node will ____ heart rate. A cholinergic agonist applied at the sinoatrial node will _____ heart rate.
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decrease ; decrease
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an antagonist will
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block the effect of an agonist.
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true or false: antagonists have their own inherent/intrinsic activity
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FALSE
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antagonists can have dramatic effect by ____ endogenous signal's activity
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blocking
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an antagonist may have no effect on ____ cells but may have big effects "_____"
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isolated ; "in context"
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autoreceptors
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presynaptic receptors for the same transmitter; a receptor located on presynaptic nerve cell membranes and serves as a part of a feedback loop in signal transduction (homeostatic manner)
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indirect drugs will ____ endogenous signals effect.
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enhance
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indirect drugs can affect NT ___, ____ and ____
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synthesis, breakdown and accumulation
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NANC stands for
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non adrenergic, non cholinergic
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nitric oxide synthasse
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synthesizes NO from arginine
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NO is a
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nonpolar gas that readily crosses cell membranes
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NO plays a role in:
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vasodilation, bronchodilation, neuronal control of GIT function
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autonomic drugs are receptor ______
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mediated
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can antagonists block exogenous agonists in addition to endogenous signals?
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yes
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describe a cholinergic synapse
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ACh packaged in synaptic vessel, released with depolarization. Activates musc/nic rc.
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what degrades ACh
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AChe
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describe an adrenergic synpase
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NEpi packaged in synaptic vessel. Released with depolarization. Activates a/b receptor. Reuptake by MAT. Degraded by MAO, COMT
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MAT
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monoamine transmitter
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MAO
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monoamine oxidase
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COMT
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Catechol-O-methyltransferase
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what degrades NEpi?
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MAO, COMT
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neurotransmission is ____ by activating postsynaptic receptors
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mediated
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neurotransmission is ____ by activating presynaptic receptors
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modulated
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indirect agonists
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increase effects of the transmitter by blocking its degradation, reuptake. Can also increase synthesis
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indirect antagonists
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decrase effects of transmitter by depleting the NT (ex: blocking vesicular packaging)
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what activates NT release?
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depolarization of the terminal region of an axon
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what is ACh synthesized from?
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choline and acetyl coenzyme A
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ACh can also interact with presynaptic cholinergic receptors invovled in ______ of ACh release
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autoregulation
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how does AChE work?
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hydrolyzes ACh to choline and acetate
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which by product of ACh breakdown is recycled?
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choline
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what transports NEpi molecules into vesicles?
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vesicular monoamine transporter (VMAT)
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which presynaptic receptors will NEpi typcally activate to inhibit further transmitter release?
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alpha 2
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are NEpi molecules degraded?
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no- taken back up into the terminal as intact NEpi
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Cholinesterase inhibitors are ___ agonists
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indirect
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how can indirect drugs work?
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block degradation of the transmitter, block reuptake, block or activate synthesis, block uptake into synaptic vesicles
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what stimulates the activity of nitric oxide synthase?
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neuronal activity
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NO diffuses into muscle cells where it activates
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guanalyl cyclase (forms cGMP)
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a mimetic will
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activate
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a lytic will
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antagonize
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parasympathomimetics
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cholinergic agonists
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parasympatholytics
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cholinergic antagonists
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sympathomimetics
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adrenergic agonists (except in sweat glands/except in horses)
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sympatholytics
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adrenergic anatogonists
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ganglionic blockers
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mainly parasympatholytic (parasympathetic tone typically dominant)
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parasympathomimetics will produce what type of effects?
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increase GI motility, increased secretions, increased bladder wall contractions, bronchospasm, inhibition of heart force/frequency.
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what type of receptors will parasympathomimetics activate?
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muscarininc/ M3
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how is muscarinic receptor activated?
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direct stim- drug binds directly to rc and acts as an agonist. Indirect stim- endogenous ACh is mediator. Inhibition of acetylcholinesterase leads to elevated endogenous acetylcholine, which then increases cholinergic receptor activation
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what is the mediator of indirect stimulation of musc rcs?
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endogenous ACh
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two functional types of drug effects in the autonomic system. Drugs will either:
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mimic the effects of the endogenous signal or counteract the effects of the endogenous signal
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Mimetic responses in parasympathetic system are elicited
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by cholinergic agonists
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Lytic responses in parasympathetic system are elicited by
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cholinergic antagonists
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Mimetic responses in sympathetic system are elicited by
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adrenergic agonists
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Lytic responses in sympathetic system are elicited by
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adrenergic antagonists
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Ganglionic blockers: while they block symp and parasymp activation, the main result is
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reduction in parasym. due to underlying “tone”
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ACHe
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typically rapidly inactivates the ach molecules, with a generally short period of receptor activation.
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You can block excessive receptor activation (or normal levels of activation) by a
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directing acting antagonist, such as atropine
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f a direct acting agonist was being used at the time, e.g., if bethanecol was being used to treat micturition difficulties, co-exposure to an anticholinesterase could elicit much more extensive enhancement
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of parasympathetic signaling
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most parasympathomimetics are mediated through M3 receptors with the exception being
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those involved in cardiac function (primarily M2 receptors)
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A direct agonist
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physically interacts with the receptor and elicits the endogenous signal-like response
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An indirect agonist works through
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modifying the actions of the endogneous signal molecule, such as when acetylcholinesterase inhibitor increases the time for acetylcholine to survive in the synapse and thus be able to activate those receptors.
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two direct cholinergic agonists
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bethanecol and pilocarpine
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bethanechol mechanism
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similar to acetylcholine but metabolized slowly
Principally muscarinic agonist |
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Bethanecol has some degree of selectivity for _____ over nicotinic receptors.
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muscarinic
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bethanecol metabolism
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slower than ACh
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why is ACh not suitable to be used as a drug?
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because of its rapid metabolism
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bethanechol effects?
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It will increase GI motility, gut secretions, and . It will increase bladder contractions and facilitate urination.
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bethanechol primary drug utility
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to increase urination, stimulate bladder contractions
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adverse effects of bethanechol?
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diarrhea or bronchospasms
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pilocarpine has a ________ ____ action
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dominant muscarinic
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pilocarpine effects
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GI activity, elicits negative chronotropy, and causes miosis.
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pilocarpine adverse effects
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diarrhea or increased secretions
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pilocarpine can be used as a ___ agent
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miotic agent
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pilocarpine can be used as a cholingergic agonist to decrease
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intraocular pressure
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two general types of cholinesterase inhibitors
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carbamates and organophosphate
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difference between carbamates and organophosphates
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carbamates are relatively short acting inhibitors; organophosphates typically inhibit for much longer times. Carbamates "reversibly" inhibit, organophosphates are irreversible
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both carbamates and organophosphates cause
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acetylcholine accumulation and prolonged/excessive stimulation of muscarinic and nicotinic receptors
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carbamates and organophosphates principally act on the
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peripheral nervous system
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two carbamate anticholinesterases
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neostimine and pyridostigmine
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do neostigmine and pyridostigmine enter the CNS?
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no, not readily
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neostigmine and pyridostigmine cause typical signs of ___ of the ParaSNS
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overactivity (incrased GI motility, increased secretios, miosis, etc)
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Why would you want to use either neostigmine or pyridostigmine?
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1)To reverse a neuromuscular blockade with drug such as tubocurarine 2)To increase smooth mm tone (e.g., after surgery) 3)To increase skeletal mm control (e.g., in mm diseases involving cholinergic signaling)
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edrophonium
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has very similar effects as neostigmine and pyridostigmine, but its action is incredibly fast (IV lasts only a few minutes)
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when is edophonium useful?
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when diagnosing myasthenia gravis- it increases mm tone for a brief period of time
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organophosphates are cholinesterase inhibitors that ______________________. Thus, the inhibition of ____ lasts much longer
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phosphorylate the active site of the enzyme; ACHe
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two indirect parasympathomimetics
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cisaparide, metaclopromide
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cisapride and metaclopromide are NOT __________ but it is thought that they increase __________________________
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cholinesterase inhibitors; ACh release in the myenteric plexus through activating serotonergic receptors.
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primary effect of cisapride and metaclopromide is ______. Primary adverse effect would be ________
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increase GI motility; too much increase leading to ab pain, diarrhea
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why are metoclopramide and cisapride used?
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To increase GI motility, i.e., to treat constipation, gastric stasis. (promotility/prokinetic agent)
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dopaminergic and serotonergic agonists/antagonists can influence GI
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motility
|
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enteric nervous system consists of
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interactions between serotonin, dopamine, NO, ACh in contraction and secretions.
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Excitatory (EM) and inhibitory (IM) motor neurons control motility and are found in the _______ throughout the GI tract
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circular and longitudinal muscle
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____ control transmission in the enteric nervous system
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interneurons
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Ascending interneurons
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contribute to local motility reflexes
|
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descending interneurons participate in
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migrating myoelectric complexes (MMCs), secretomotor reflexes (REFLEX), as well as local motility reflexes.
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Secretomotor neurons (SM) have both _________ functions
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secretory and vasodilator
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Intrinsic primary afferent nerves (IPAN) respond to
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chemical stimuli or distension in the gut, thereby exerting actions on blood flow and secretion.
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___________ of the GI tract conveys information from the enteric nervous system to the brain and vice versa
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extrinsic innervation
|
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examples of resident and infiltrating immune cells that are found largely in the mucosa in physiological states and during states of inflammation
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mast cells and macrophages
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Immune cells express cannabinoid receptors and release ________ as chemical mediators, potentially altering gut function.
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endocannabinoids
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eCB receptors are found in
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CNS, PNS, immune cells
|
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antinociceptive effecs of cannabinoids are mediated, in part, at the
|
spinal level
|
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_____ is the prototype parasympatholytic
|
atropine
|
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atropine directly binds to all subtypes of
|
muscarinic receptors
|
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atropine has some higher selectivity for ____ salivation and bronchial secretions and sweating (Except in horses)
|
decreasing
|
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atropine can be used as a ___ agent and to temporariliy paralyze the ______ m.
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mydriatic; ciliary
|
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atropine effects
|
increase heart rate, decrease GI motility,
|
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atropine can cross the _____ and block ____ receptor signalling in the CNS
|
BBB; muscarinic
|
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why does atropine need to be used with extreme caution in horses?
|
decrease in gut motility results in colic
|
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atropine side effects
|
photophobia, xerostomia, and hyperthermia
|
|
when is atropine indicated?
|
useful preanesthetic, first like of defense with OP intoxication, treat bronchoconstriction, increase heart rate
|
|
why is atropine useful as a preanesthetic?
|
decreases respiratory secretions, reduces movement in bowels, bladder
|
|
four other antimucsarinic drugs
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aminopentamide, Propantheline, glycopyrrolate, and tropicamide
|
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aminopentamide has some selectivity for the ____ system
|
GI
|
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tropicamide is used more in
|
opthamology
|
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aminopentamide, Propantheline, glycopyrrolate, and tropicamide all act like ____, but cannot __________
|
atropine; cross the BBB
|
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there is a ____ ____ of symp and parasymp activity
|
resting tone
|
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the dominant resting tone for vasculature is
|
sympathetic
|
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the dominant tone for essentially all other autonomic functions is
|
parasympathetic
|
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if autonomic ganglia stimulation is blocked, what will be observed is a NET decrease in parasympathetic function in
|
almost all tissues except the blood vessels
|
|
effects of a ganglionic blocker
|
heart rate (a net reduction in parasympathetic function), decrease GI motility, decrease bladder function, increase eye pupil opening, reduce ciliary mm function, decrease salivation and other secretions (e.g., bronchial).
|
|
hexamethonium is a competitive blocker of
|
nicotinic r
|
|
dysautonomia
|
Degeneration of neurons in the autonomic ganglia with associated failure of sympathetic and parasympathetic functions.
|
|
common signs of dysautonomia include
|
urinary retention, thick nasal discharge, photophobia (mydriasis), anorexia, weight loss
|
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canine dysautonomia primariliy is a net reduction in
|
parasympathetic functions (functions under predominant parasymp tone)
|
|
three therapies of dysautonomia
|
bethanechol (improvement in secretions/urination), pilocarpine (eye drops to reduce photophobia), metoclopramide/cisapride (incraese GI motility)
|
|
effects of hexamethonium
|
tachycardia, decreased GI motility, mydriasis, urinary retention, dry mouth. Vasodilation/hypotension due to blocking dominant vascular symp tone
|
|
dysautonomia is a lesion of
|
cell bodies in autonomic ganglia
|
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phenylpropanolamine is a mixed sympathomimetic. it is sometimes used topically to treat nasal congestion. Why is it appropriate for this purpose?
A) it can activate B2 receptors in the nasal vasculature leading to vasodilation B) it can activate B1 receptors in the nasal vasculature leading to vasoconstriction C) it can activate alpha receptors in the nasal vasculature leading to vasoconstriction D) it can activate nicotinic receptors at the autonomic ganglia leading to vasoconstriction |
C) it can activate alpha receptors in the nasal vasculature leading to vasoconstriction
|
|
medetomidine is an a2 receptor agonist that has sedative and analgesic properties. aside from these useful traits of anesthesia, what is an important propety of this drug?
a) it activates b2 receptors in the vessel of the kidney b) it typically increases the amount of anesthesia needed c) it typically decreases the amount of volatile anesthesia needed d) it activates nicotinic receptors at autonomic ganglia |
c) it typically decreases the amount of volatile anesthetic needed
|
|
metoclopramide is a prokinetic agent. why would you use this type of drug?
a) if you needed to increase the RBC concentration in the blood b) if the patient had a distended urinary bladder c) if the patient had megacolon d) none of the above |
c) if the patient had megacolon
|
|
what would happen to heart rate following systemic administration of isoproterenol?
a) increase because of direct b1 receptor activation b) increase because of indirect b1 receptor activation c) increase because of direct b2 receptor activation d) increase because of indirect B2 receptor activation |
a) increase because of direct b1 receptor activation
|
|
propantheline is
a) an antimuscarinic useful as a preanesthetic agent b) an antimuscarinic useful for treating tachycardia c) an antimuscarinic that readily crosses the BBB d) all of the above |
c) an antimuscarinic that readily crosses the BBB
|
|
terbutaline is a direct b2 agonist and effective bronchodilator. if you injected this drug intradermally, what response might you anticipate?
a) reduction in local sweating if the patient is a horse b) increase in local sweating if the pateitnt is a horse c) reduction in local swearint if the pateint is a dog d) increase in local sweating if the patient is a dog |
b) increase in local sweating if the patient is a horse
|
|
the ileal muscle can sometimes lose tone (atony) following sx procedures. which of the following drugs might be useful to treat this condition?
a) aminopentamide b) propanolol c) clenbuterol d) neostigmine |
d) neostigmine
|
|
dopamine is effective for treating shock because
a) it increases NEpi release to enhance cardiac b1 receptor activation and icnrease cardiac output b) it increases renal blood flow through direct activation of dopamine D1 c) both a and b are true d) neither a or b are true |
c) both a and b are true
|
|
bethanecol is a drug that can be used to treat dysautonomia, why is it useful?
a) it increases GI motility by activating M3 rc b) it increases heart rate by activating b1 rc c) it incraeses urinary output by activating m3 rc at the detrusor m d) bethanecol should not be used in dysautonomia |
c) it increases urinary output by activating m3 receptors at the detrusor muscle
|
|
pheochromocytoma is a tumor of the adrenal gland associated with elevation of serum catecholamines. which of the following drugs might be useful for treating this tumor?
a) phenoxybenzamine b) phenylephrine c) dobutamine d) medeomidine e) none of the above |
a) phenoxybenzamine
|
|
if you injected turbutaline by ID route and detected a drop in systemic blood pressure, what might have happened
a) it may have gained access to the systemic circulation and blocked cardiac b1 rc b) it may have gained access to the systemic circulation and blocked vascular b2 rc c) it may have gained access to the systemic circulation and activated cardiac b1 rc d) it may have gained access to the systemic circulation and activated vascular b2 rc |
d) it may have gained access to the systemic circulation and activated vascular b2 rc
|
|
we discussed how NEpi adminstered systemically can lead to a reflex bradycardia. Why does this happen?
a) NEpi markedly increases blood pressure which then activates the baroreceptor reflex to decrease heart rate b) NEpi activates b2 rc which decreases blood pressure and in turn decreases heart rate c) NEpi causes an increase in the release of Epi from the adrenal gland when then leads to reflex reduction in heart rate d) none of the above |
a) NEpi markedly increases blood pressure which then activates the baroreceptor reflex to decrease heart rate
|
|
activation of this rather short, postganglionic neuron leads to NO release, which in turn relaxes the urethral sphincter. Where is the location of the cell bodies of the preganglionic neurons which innervate the ganglia of this type of postganglionic neuron?
a) midbrain b) thoracic cord c) lumbar cord d) sacral cord e) none of these |
d) sacral cord
|
|
cisapride and metoclopramide are both indirect parasympathomimetics that can be used as prokinetic agents. how do they work?
a) they block acetylcholine release in the myenteric plexus b) they enhance ACh release in the myenteric plexus c) they block NEpi release in the mytenteric plexus d) they enhance NEpi release in the myenteric plexus |
b) they enhance ACh release in the myenteric plexus
|
|
the catecholamines epi, nepi, and isoproterenol can differentially affect blood flow thru the muscles (eg, femoral blood flow). based on their receptor selectivity (a and b as well as subtypes) the following relative femoral blood flow responses are seen with IV administration of
Epi: NEpi : ISO a) intermediate blood flow : highest blood flow : lowest blood flow b) lowest : intermediate : highest c) highest : intermediate : lowest d) intermediate : lowest : highest |
d) intermediate : lowest : highest
|
|
metoprolol is a b1 antagonist. what condition would this be best suited for treating?
a) photophobia b) xerostomia c) reversal of medetomidine sedation d) cardiac tachy arrhythmia |
d) cardia tachy arrhythmia
|
|
nephrosplenic ligament entrapment in horses is the physical consitriction of a the large colon by the left kidney and spleen, such that congestion in both spleen and colon occur. a direct a1 agonist can contract the spleen and sometimes rectify this problem. which of the following drugs might be used?
a) clenbuterol b) cisapride c) propantheline d) phenylephrine e) terbutaline |
d) phenylephrine
|
|
which of the following is an inappropriate use of a compounded drug?
a) purchanse of a compounded drug for use in a horse. the drug is no longer manufacturedL it was removed from the human marked due to severe adverse effects in humans b) purchase of a manufactured human injectable drug compounded for topical use in a cat c) purchanse of a manufactured cattle antibiotic compounded at a lower concentration for use in a dog with chronic urinary tract infection d) purchase of a compounded alternative for Clomicalm |
d) purchase of a compounded alternative for clomicalm
|
|
which of the following statements cmoparing manufactured drugs and compounded drugs is true?
a) compounded drugs in the us must be formulated from FDA approved bulk chemicals b) generic manufactured drugs are not quality controlled by the FDA c) all legal risk incurred when a vet prescribes a compounded drug to a patient is assumed by the compounding pharmacy d) expiration dates on compounded drugs may not be based on satbility testing and therefore may not be correct |
d) expiration dates on compounded drugs may not be based on satbility testing and therefore may not be correct
|
|
which of the following properties of a drug is likely to be associated with hyperpolarization?
a) drug facilitates Cl channel opening b) drug blocks NEpi reuptake transport c) drug inhibits monoamine oxidase A d) drug is an agonist at NMDA glutaminergic ionotropic rc |
a) drug facilitates Cl channel opening
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in most species, sympathetic neurons innervating this particular effector release Ach to activate cholinergic rc on the effector cells. what is the end organ innervated by these sympathetic cholinergic neurons?
a) sweat gland b) salivary gland c) ocular radial m d) renal blood vessel |
a) sweat gland
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activation of alpha receptors in the sympathetic system is typically stimulatory in nature except for those residing in the
a) heart b) lungs c) GI tract d) blood vessels |
GI tract
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isoproterenol is used to treat bronchospasm due to its ability to
a) activate a-adrenergic rc b) activate b-adrenergic rc c) block a- adrenergic rc d) block b-adrenergic rc |
b) activate beta adrenergic rc
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pilocarpine is a direct muscarinic agonist. if instilled into the eye:
a) contraction of the radial m will follow b) contraction of the ocular sphincter m will occur c) contraction of the ciliary m will result d) both b and c are true |
b) contraction of the ocular sphincter muscle will occur
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at low dosages (<10ug/kg iv in dogs) dopamine will
a) activate b1 receptors in cardiac m b) increase nepi release in symp fibers innervating the heart c) increase renal blood flow thru activation of dopamine receptora d) activate a1 rc in peripheral vessels e) all except D |
a) activate beta 1 rc in cardiac muscles
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epi causes an increase in blood pressure following systemic administration. coexposure to an alpha blocker causes
a) hypotension because of net increased activation of b2 receptors by epi b) no effect becaues epi has no action at a rc c) no effect because epi has no action at b rc |
a) hypotension becaues of net increased activation of beta 2 rc by epi
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ephedrine is a mixed adrenergic agonist that can work by both increasing Nepi release from symp neurons and by directly activating both a and b rc. it could be used to
a) dilate bronchioles b) treat urianry incontinence c) treat nasal congestion d) all of the above |
d) all of the above
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following sx including insertion of a urinary bladder catheter, the bladder smooth muscle may become immobile. which drug might you use to increase bladder detrusor muscle motility?
a) atropine b) hexamethonium c) neostigmine d) aminopentamide |
c) neostigmine
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a cat is brought into a clinic presenting with excessive secretions (tearing, salivation, urination). Skeletal muscle fasciculations are present. Upon ocular exam, miosis is observed. Pulmonary auscultation indicates labored breathing with probably obstructive secretions in the upper airways. Atropine is administered and all signs except muscle fasciculations improve. What is the most likely explanation?
a) the cat got into some atropa belladonna b) the cat ate muscarine containing mushrooms c) the cat was exposed to an AChE-inhibiting insecticide d) the cat has dysautonomia |
c) the cat was exposed to an AChE-inhibiting insecticide
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metoclopramide is a prokinetic agent (will increase transit thru the GI tract). it is acting as a parasympathomimetic in this setting. it elicits this response by
a) directly acvtivating muscarinic rc in gi smooth m b) directly activating beta2 rc in Gi smooth m c) directly activating serotonin rc in GI smooth m d) directly activating dopamine rc in GI smooth m |
c) directly acvitvating serotonin rc in gi smooth m
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colic in a horse is a possible consquence with ocular administration of this agent
a) atropine b) isoproterenol c) propantheline d) phentolamine e) propanol |
a) atropine
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aminopentamide has a relative selectivity for blocking musc rc in the
A) heart b) airways c) GI smooth m D) CNS |
c) GI smooth M
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canine dysautonomia involves loss of neurons in autonomic ganglia from an unknown etiology. this leads to subsequent loss of innervation to both symp and parasymp end organs. three common signs in this condition: 1) thick, viscous nasal secretions, 2) dilated pupils, 3) distended bladder, suggest that either the parasymp or symp system is predominantly affected. Which branch of the autonomic nervous system appears most affected in canine dysautonomia?
a) symp b) parasymp |
b) parasympathetic
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what might you expect if a cow was exposed to botulinum toxin?
a) excitation of musc rc in the heart b) exictation of the nicotinic rc in the somatic m c) excitation of nicotinic rc in the autonomic ganglia d) none of the above |
b) excitation of nicotinic rc in the somatic m
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sodium nitroprusside is a drug that releases NO when given systemically. knowing what you know about the effects of NO, what would you expect to occur
a) increased GI tract motility b) incraesed cardiac muscle contraction c) increased vasodilation d) increased blood pressure |
increased vasodilation
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the pevlic n originates from the sacral cord to innervate the bladder smooth m to contract. this nerve is a
a) symp n that releases nepi b) parasymp n that releases nepi c) symp n that relases dopamine d) parasymp n that releases ACh e) parasymp n that releases NO |
d) parasymp n that releases ACh
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an a2 adrenergic rc is often located on the presynaptic noradrenergic neuron termincal region where it typically:
a) stimulates nepi release b) inhibits nepi release c) inhibits epi release d) inhibits ACh release |
b) inhibits Nepi release
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clenbuterol is a selective b 2 rc agonist. you would consider using this when
a) increased cardiac contractile force is needed b) selective vasodilation c) decreased nepi release from adrenergic neurons would be advantageous d) decreased bronchial smooth m contractions is needed |
d) decreased bronchial smooth m contractions is needed
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which drug would be expected to incraese nepi release by blockign adrenergic autoreceptors on symp nerve terminals?
a) yohimbine b) atenolol c) propanolol d) clonidine e) isoproterenol |
d) clonidine
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megacolon is a chronic dz that causes ieleus of the colon and requires long term therapy. which one of the following drugs is potentially usefin in treating a cat with megacolon?
a) metaclopramide b) cisapride c) apomorphine d) lidocaine by CRI e) diazepam |
b) cisapride
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which of the following promotes termination of effects induced by sympathetic postganglionic neurons?
a) MAO activity b) catechol-O-methyltransferase activity c) reuptake of Nepi into the postganglionic neuron d) a and b e) all of the above |
e) all of the above
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which of the following agents can be used in combo with neostigmine for reversal of competitive neuromuscular blocking agents to prevent the muscarinic effects of neostigmine?
a) bethanecol b) pilocarpine c) glycopyrrolate d) edrophonium e) atenolol |
c) glycopyrrolate
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which of the following tissues/organs is predominantly under the control of the symp nervous system
a) GI smooth m b) arterioles and veins c) myocardium d) eye e) b and c |
b) arterioles and veins
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which of the following is most likely to cause bronchospasm as an adverse effect?
a) atropine b) propantheline c) propanolol d) phenyoxybenzamine e) clenbuteral |
c) propranolol
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which of the following is most likely to cause hypertension as an adverse effect?
a) phenyephrine b) isoproterenol c) yohimbine d) phenoxyybenzamine e) terbutaline |
a) phenylephrine
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which of the following species is most sensitve to the depressent effects of atropine of GI motility
a) rabbit b) dog c) cattle d) horse e) cat |
d) horse
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which of the following agents is the safest to use a bronchdilator in an animal with cardiac dz?
a) clenbuterol b) isoproterenol c) propanolol d) epi e) atenolol |
a) clenbuterol
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which of the following effects is most likley to be observed after administration of hexamethonium?
a) tachycardia b) hypertension c) miosis d) incraesed peristalsis e) increased salivation |
a) tachycardia
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which of the following is unlikley to be a toxic symptomarising from excessivei nhibition of AChE?
a) salivation b) miosis c) tachycardia d) urination e) defecation |
c) tachycardia
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which of the following has the shortest duration of action?
a) atropine b) pyridostigmine c) dopamine d) propranolol e) atenolol |
c) dopamine
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edrophonium is useful in diagnosis and pyridostigmine useful in tx of myasthenia gravis because:
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both edrophonium and pyridostigmine are indirect cholindergic agonists that can stimulate cholinergic rcs in the muscles. edrophonium's action is much shorte than pyridostigmine
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epi is a more potent a agonist than nepi, but if both are injected IV at equivalent dosages, nepi causes greater blood pressure increase. this is because
a) nepi induces the release of dopamine at dopaminergic nerve terminals mediating vasoconstriction b) nepi is a more potent agonist at b1 rc leading to more pronounced positive ionotropic response c) epi is a more potent agonist at b1 rc in vessel beds mediating vasodilation d) epi is a more potent agonist at b2 rc in vessel veds mediating vasodilation |
d) epi is a more potent agonist at b2 rc in vessel beds mediating vasodilation
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when using a local anesthetic agent to perform a nerve block, the duration of action can be prolonged by
a) coadministration of epi to activate b2 rc, thus leading to vasoconstriction and lesser systemic absorption of the anesthetic b) coadministration of epi to activate a1 rc, thus leading to vasonconstriction and lesser system absorption of the anesthetic c) coadministration of nepi to activate b2 rc, thus leading to vasodilation and lesster systemic absorption of the anesthetic d) coadministration of nepi to acviate a1 rc, thus leading to vasoconstriction and greater system absorption of the anesthetic |
b)coadministration of epi to activate a1 rc, thus leading to vasonconstriction and lesser system absorption of the anesthetic
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dobutamine is a b1 agonist. it is useful for
a) short term tx of heart failure b) short term tx of bronchospasm c) short term tx of cardiac arrhythmia d) short term tx of urinary incontience |
a) short term tx of heart failure
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atenolol is a b1 antagonist. based on receptor selectivity, what condition would this be best suited for treating
a) bronchospasm b) cardiac arrhythmia c) urinary incontinence d) reversal of xylazine anesthesia |
b) cardia arrhythmia
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binding of an agonist to b2 rc is associated primarily with which of the following effects?
a) tachycardia B) incrased salivation c) mydriasis d) bronchodilation e) incrased GI motility |
d) bronchodilation
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which of the following agents is the safest to use a bronchdilator in an animal with cardiac dz?
a) terbutaline b) isoproterenol c) propanolol d) dobutamine e) atenolol |
a) terbutaline
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which of the following is most likley to cause vasodilation in m, vasoconstriction of cutaneous vessels, and positive chronotropic and inotropic effects on the heart?
a) isoproteerenol b) nepi c) ach d) epi e) dopamine |
d) epi
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if propranolol is administered, followed by epi, what effects of epi will be observed?
a) increased heart rate b) bronchodilation c) mydriasis d) a and b e) all ofthe above |
c) mydriasis
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at low to moderate doses, dopamine has a following pharm effects?
a) vasodilation of coronary vasculature b) positive inotripic effect c) vasodilation of mesenteric vasculature d) a and b e) all of the above |
e) all of the above
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which of the following agents can be used to reverse the effects of a2 agonists such as xylazine?
a) glycopyrrolate b) neostigmine c) yohimbine d) prazosin e) a and b |
c) yohimbine
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which of the following adrenergic agonists will cause in an increase in both heart rate and peripheral resistance?
a) nepi b) epi c) isoproterenol d) low to mod dose of dopamine e) clenbuterol |
b) epi
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which of the following agents would be most appropriate for blocking adrenergic rc in the heart of an asthmatic patient?
a) phenoxybenzamine b) propranolol c) prazosin d) yohimbine e) atenolol |
e) atenolol
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which of the following rc or nt produces biological effects by means of an ion channel?
a) nicotinic b) muscarinic c) GABA d) a and C e) all off the above |
d) a and c
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which of the following drugs would be most effective at reversing the effects of xylazine or clonidine (a2 receptor agonists)
a) glycopyrollate b) yohimbine c) aminopentamide d) terbutaline e) prazosin |
b) yohimbine
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dysautonomia is assocated with a loss of neurons in the autonomic ganglia. If ganglionic neurons are lost nonselectively, this could potentially reduce activation of both sympathetic and parasymp systems. in dysautonomia, however, there is a general reduction in parasym control, leading to mydriasis, thick nasal secretions, photophobia and difficulting urinating with a distended urinary bladder. why is this?
a) parasym tone is predominant over symp tone regulating pupillary constriction, airway secretions and urination b) symp tone is predominant over parasymp tone regulating pupillary constriction, airway secretions and urination c) relative predominance of symp/parasymp tone has nothing to do with it |
a) parasymp tone is is predominant over symp tone regulating pupillary constriction, airway secretions and urination
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if a cat had excessive spasmodic GI movements and diarrhea, which of these drugs would be reasonable to use?
a) neostigmine b) bethanecol c) pilocarpine d) aminopentamide e) metoclopramide |
d) aminopentamide
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for which of the following conditions would the nonselective b agonist isoproterenol be best suited to treat
a) hypotension b) urinary incontience c) bronchospasm d) reversal of xylazine anesthesia |
c) bronchospasm
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glycopyrollate is
a) an antimuscarinic useful as a preanesthetic agent b) an antimuscarinic useful for treating bradycardia c) an antimuscarinic with little cns effect d) all of the above |
d) all of the above
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epi given IV can increase blood pressure due to both activation of cardiac b1 rc leading to increased heart contraction and activation of a1 rc leading to vasoconstriction. in the presence of which of the following types of drugs would you get epi reversal (ie, drop in blood pressure following epi dosing)
a) a rc blocker b) b rc blocker c) a agonist d) b agonist |
a) a rc blocker
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ephedrine is a mixed adrenergic agonist (Acts directly and thru increased release of nepi). it is sometimes used to treat urinary incontinence in small animals. why is it effective for this purprose?
a) ephedrine can activate b3 rc on the bladder wall to decrase detrusor m contractions b) in can activate b3 rc in the internal sphincter m to cause net relaxation of the sphincter c) in can activate a receptors in the internal sphincter m to cause net contraction of the sphincter d) it can activate nicotinic rc to increase sphincter m contraction |
c) it can activate a rc in the internal sphincter m to cause net contraction of the sphincter
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A dog shows bradycardia, excessive urination, diarrhea, and airway secretions. which drug could be used?
a) glycopyrrolate b) bethanecol c) metoclopramide d) none of the above |
a) glycopyrrolate
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where is the anatomical site of action of nicotine and nicotine like drugs?
a) at symp ganglia b) at parasymp ganglia c) at neither ganglia d) at both ganglia |
d) at both ganglia
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sympathomimetic agents that affect SNS
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NEpi, Epi, Isoproterenol, dopamine
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sympatholytic agents that affect SNS
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phentolamine, phenoxybenzamine, propranolol
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sympathomimetics (a rc)
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produce peripheral excitation, vasoconstriction of cutaneous, mucosal, splanchnic and renal vessels
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sympathomimetics (b rc)
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peripheral inhibition (relaxation of bronchial and GIT smooth m), vasodialuation of skel vasculature, cardiac excitatoy action (inotropic/chronotropic), metabolic (glyocogenolysis, mobilization of fatty acids)
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catacholamine MOA
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direct agonism (a and b)
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cocaine MOA
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inhibit reuptake of NEpi in presynaptic terminal
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amphetamine MOA
|
increased release of NE --> mixed effects
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MAO inhibitor effects
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indirect agonism, leads to accumulation of NEpi (mostly central) and EPI (antidepressants)
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how can drug effects be modified in vivo?
|
reflex compensation
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which agonists are most effective on a rc? Where are they?
|
Epi > Ne >>>> Iso, in blood vessels (vasoconstriction)
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which agonists are most effective on B1 rc? Where are they?
|
iso > epi >>= NE; heart
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which agonists are most effective on B2 rc? Where are they?
|
Iso > epi >>>>> NE; blood vessels (vasodilation)
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what rc will NE act on?
|
a1, a2, b1 (direct)
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which rc will EPI act on?
|
a1, a2, b1, b2 (direct acting)
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which rc will DA act on?
|
a1, a2, b1, D (mixed acting, also incrases Nepi release)
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which rc will ISO act on?
|
b1, b2 (direct acting)
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do catecholamines easily cross the BBB?
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no
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how are catecholamines eliminated?
|
rapid inactivation, involves diffusion, reuptake, and MAO/COMT metabolism
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most Nepi effects are in the ____ system
|
cardiovascular
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EPI effects
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relaxation of GI smooth muscle/contraction of sphincters, urianry retention, bronchodilation, mydriasis, splenic contraction
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ISO effects
|
bronchodilation and GI smooth muscle relaxation
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therapeutic indications of NE
|
limited use
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therapeutic indications of EPI
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bronchospasm, cardiac rescusc, hypersens rxns/anaphylactoid shock, vasoconstriction due to prolonged effects of local anesthetics, localized hemorrhage
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thereapeutic indications of ISO
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cardiac stim in heart block, bronchospasm
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DA therapeutic indications
|
hypotension, shock (part with oliguria in conjunct with fluid replacement) acute heart failure
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how do indirect agonists work?
|
inhibit reuptake, increase release, inhibit breakdown
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why is Da a mixed acting agonist?
|
also increases Nepi release
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why is DA useful in shock, only at low doses?
|
low doses cause increase NE release in the heart, activation of B1 rc and overall excitation. Also causes vasodilation of renal and mesenteric vessels via D1. BUT high doses cause system vasoconstriction via a receptors
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how are catecholamiens generally given?
|
IV
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phenylephrine
|
a1 agonist
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dobutamine
|
b1 agonist
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clonidine, xylazine, medetomidine
|
a2 agonists
|
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terbutaline, clenbuterol, albuterol
|
b2 agonists
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ephedrine
|
mixed, indirect mimetic with some direct a1 and b action)
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phenylpropanolamine
|
mixed indirect mimetic with some direct a1 action
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phenoxybenzamine
|
a antagonist
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prazosin
|
a1 blocker
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yohimbine, tolazoline, atipamezole
|
a2 antagonists, competitive
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propranolol
|
non selective b blocker
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atenolol, metoprolol, esmolol
|
b1 antagonist
|