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64 Cards in this Set
- Front
- Back
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What is the pathway that Acetylcholine takes from it's creation the neuronal axon back to start?
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1. Synthesis 2. Storage in Vessicles 3. Release of Neurotransmitter 4. Binding to the Receptor 5. Degradation of acetylcholine 6. Recycling of choline
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What are cholinergic type receptors?
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Muscarinic (M1, M2, M3) and Nicotinic (Nn and Nm)
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Where are muscarinic M1 receptors typically located?
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CNS neurons, sympathetic postganglionic neurons, some presynaptic sites;
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What is the result of ligand binding of muscarinic M1 receptors?
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Formation of IP3 and DAG, increased intracellular calcium.
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Where are typical locations of Nicotinic Nn receptors?
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Postganglionic neurons, some presynaptic cholinergic terminals.
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What is the result of ligand binding to Nn receptors?
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Opening of Na+, K+ channels, depolarization
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What are the typical locations of Nicotinic Nm receptors?
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Skeletal muscle neuromuscular endplates.
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What is the result of ligand binding to the Nm receptors?
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Opening of Na+, K+ channels, depolarization.
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What is the typical location of Alpha1 receptor?
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Postsynaptic effector cells, especially smooth muscle.
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What is the result of ligand binding to Alpha1 receptors?
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Formation of IP3 and DAG, increased intracellular calcium.
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What is the result of ligand binding to Alpha2 receptors?
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Inhibition of adenylyl cyclase, decreased cAMP.
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What is the result of ligand binding to Beta1 receptors?
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Stimulation of adenylyl cyclase, increased cAMP.
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What is the result of ligand binding to Beta2 receptors?
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Stimulation of adenylyl cyclase, increased cAMP.
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What is the result of ligand binding to Beta3 receptors?
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Stimulation of adenylyl cyclase, increased cAMP.
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What is the typical location of Alpha2 receptors?
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Presynaptic adrenergic nerve terminals, platelets, lipocytes, smooth muscle
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What is the typical location of Beta1 receptors?
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Postsynaptic effector cells, especially heart, lipocytes, brain, presynaptic adrenergic and cholinergic nerve terminals.
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What is the typical location of Beta2 receptors?
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Postsynaptic effector cells, especially smooth muscle and cardiac muscle.
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What is the typical location of Beta3 receptors?
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Postsynaptic effector cells, especially lipocytes.
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What is a cholinergic crisis?
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The clinical condition of excessive activation of cholinoceptors; it may include muscle weakness as well as parasympathetic signs.
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What is a direct-acting cholinomimetic?
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A drug that binds and activates cholinoceptors; the effects mimic those of acetylcholine.
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What is EDRF?
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Endothelium-derived relaxing factor which is a potent vasodilator substance, largely nitric oxide that is released from vascular endothelial cells.
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What is an indirect-acting cholinomimetic?
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A drug that amplifies the effects of endogenous acetylcholine by inhibiting achetylcholinesterase.
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Muscarinic agonist
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A cholinomimetic drug with primarily muscarine-like actions.
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What is a Myasthenic Crisis?
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In patients with myasthenia, an acute worsening of symptoms; often caused by inadequate cholinomimetic treatment.
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What is a nicotinic agonist?
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A cholinomimetic drug with primarily nicotine-like actions.
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What is organophosphate aging?
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A process whereby the organophosphate, after binding to cholinesterase, is chemically modified and becomes more firmly bound to the enzyme.
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What is a parasympathomimetic?
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A drug whose effects resemble those of stimulating the parasympathetic nerves.
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What is parasympathomimetic agonist?
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Muscarinic agonists
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What are the adverse affect of cholinolytic agents?
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Xerostomia, cycloplegia, photophobia, CNS stimulation/depression, precipitates attack acute glaucoma, atropine flush, constipation, tachycardia, anhidrosis, heat stroke, urinary retention
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Atropine
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found in deadly (belladonna) nightshade and jimson weed 3-4 hours for miotic agent (cholinolytic )
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Scopolamine
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found in henbane, long acting choinolytic drug (cholinolytic)
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Propantheline
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slows gastric emptying (used for peptic ulcer disease (but H2 blockers more common) (cholinolytic)
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Pirenzepine
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slows gastric emptying and preferentially blocks M1 receptor(cholinolytic)
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Hyoscyamine sulfate (Nulev)
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irritable bowel syndrome
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Cyclopentolate (12-16 hours), Tropicamide (hours), Homatropine (several days)
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topical mydriatics
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Ipratropium
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bronchodilator used in asthma
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Oxybutynin
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incontinence and urgency (virtually no xerostomia)
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Tolterodine
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incontinence and urgency (virtually no xerostomia)
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Cholinolytic agents have many therapetuic uses
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Mydriasis and cylcoplegia, peptic ulcer treatment, herperactive or IBS, symptomatic relief acute rhinitis, antidote for cholinomemetic overdose, mushroom poisoning, hyperactive carotid sinus reflex, antiparkinsonism, motion sickness, preanesthetic
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Ganglionic neurotransmission therapeutic uses (Ganglionic Blocking Drugs)
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Hypertensive cardiovascular disease emergency (disecting aortic aneurysm, controlled hypotension in surgery (neuro/skin), autonomic hyperreflexia with massive sympathetic discharge (common in sp. cord injury), acute pulmonary edema to reduce pulmonary vascular resistance
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What is predominant system in arterioles? how does ganglionic blockade effect them?
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Sympathetic; vasodilation, increased peripheral flow
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What is predominant system in veins? how does ganglionic blockade effect them?
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Sympathetic; venous pooling of blood with decreased cardiac output
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What is predominant system in heart? how does ganglionic blockade effect them?
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Parasympathetic; tachycardia
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What is predominant system in iris? how does ganglionic blockade effect them?
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Parasympathetic; mydriasis
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What is predominant system in the ciliary muscle? how does ganglionic blockade effect them?
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Parasympathetic; cycloplegia
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What is predominant system in the GI tract? how does ganglionic blockade effect them?
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Parasympathetic; decreased tone and motility, constipation
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What is predominant system in the bladder? how does ganglionic blockade effect them?
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Parasympathetic; urinary retention
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What is predominant system in the salivary glands? how does ganglionic blockade effect them?
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Parasympathetic; xerostomia
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What is predominant system in the sweat glands? how does ganglionic blockade effect them?
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Sympathetic; anhidrosis
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What is a nicotinic receptor agonist and what are its affect?
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Nicotine - increase HR, CNS stimulant; pesiticide can cause nicotine poisoning
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What are three nicotinic-ganglinic receptor antagonists?
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Hexamethonium-classical, Mecamylamine - can enter CNS, Trimethaphan - cannot enter CNS (these drugs are very dirty)
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What are the adverse affects of ganglionic blockers?
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Visual disturbances, xerostomia, urinary retention, impotence, CNS stimulation followed by depression, marked hypotension (including postural hypotension), constipation
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What are the therapetic uses of neuromuscular blockers?
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Muscle relaxation during anesthesia and surgery, prevent trauma from electroconvulsive shock therapy, reduce muscle spasms (diaphragm last!)
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d-Tubocurarine
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Prototype of non-depolarizing blocker; competitve Nm-R blocker, poor oral absorption; fast onset, longer acting, excreted liver and kidney, ganglionic blockade - decreases BP and venous return, vasodilation, release of histamine - vasodilation and bronchoconstriction
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Vecuronium (Norcuron)
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competitive Nm-R blocker, short acting, minimal ganglionic blockade, no histamine release, no change in heart rate or blood pressure
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Mivacurium
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competitive NmR blocker, ultrashort onset and duration of action, hydrolyzed by plasma cholinesterases, no effect on ganglionic transmission or cardiac M2 receptors, can cause histamine release (good alternative)
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Succinylcholine
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depolarizing antagonist, fast onset, short acting, release of histamine, no ganglionic blockade-depends on dose, hydrolyzed by pseudocholinesterase, release of K+, can result in arrhythmias, C-V reactions depends on ganglionic stimulation, can see decreased HR, BP (vagal) or increased BP (sympathetic)
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What are the adverse effects of neuromuscular blockers?
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Apnea, bronchoplasm, hypotension; 1. histamine relaxes arterioles, ganglionic blockade, pooling blood in muscles with paralysis
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What is an antidote for nondepolarizing neuromuscular blockers?
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Neostigmine or other ACHE inhibitor and supportive respiration it competes for binding with depolarizing antagonist
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What are the adverse effects of succinylcholine?
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Bradycardia, muscle pain after use, hyperkalemia, increased intraocular pressure important in patient with known glaucoma
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What can gaseous anestetics and succinylcholine (adversely) cause?
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General NM rigidity, elevated temperature, increases creatine phosphokinase and produce a syndrome-malignant hyperthermia
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Dantrolene
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blocks release of Ca2+, given PO, IV metabolized microsomes
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What is Dantrolene used for?
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a muscle relaxant used to treat spasticity due to stroke, spinal injury, multiple sclerosis, cerebral palsy, to treat malignant hyperthermia
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What are the side effects of Dantrolene?
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Dose-dependent muscle weakness, dizziness, drowsiness, fatigue, diarrhea, liver dysfunction increase aspartate aminotransferase; Counter Indications-Liver Disease, respiratory muscle weakness
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