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113 Cards in this Set
- Front
- Back
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where are alpha 1 receptors found?
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iris radial mm
arterioles veins gut sphincters trigone and sphincter of bladder sweat glands |
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what do alpha 2 receptors do?
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vasomotor sympathetic control-decrease transmission
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mechanism of action of alpha 1 receptors?
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stimulation of PLC with formation of IP3 and DAG, increased cytosolic Ca-smooth mm. contraction
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mechanism of action of alpha 2 receptors?
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inhibition of adenylyl cyclase, activation of K channels, inhibition of neuronal Ca channels- loss of action
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where are beta 1 receptors found?
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heart:
SA node- increase HR atria- increase contractility and conduction velocity AV node- same Purkinje system- same ventricles- same and pacemaker increase |
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where are beta 2 receptors found?
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arterioles and veins- dilation
tracheal and bronchiolar mm-relaxation gut motility and tone- decrease renin secretion- increase detrusor- relaxation skeletal mm- contractility liver- gluconeogenesis, glycogenolysis |
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mechanism of action for beta 1 receptor?
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activation of adenylyl cyclase and Ca channels
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mechanism of action for beta 2 receptors?
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activation of adenylyl cyclase
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receptors affected by NorEp?
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alpha 1,2 and Beta 1
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administration of NorEp?
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usually IV, orally ineffective
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factor making drugs orally effective?
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removal of OH groups
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beta 1 effect on heart?
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increase HR and myocardial contractile force
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use of NorEp?
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increase BP
improve left ventricular contractility local vasospasm |
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side effects of NorEp?
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anxiety
cardiac arrhythmia necrosis at SQ or IM sites due to vasospasm |
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receptors affected by Ep?
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alpha 1, beta 1,2
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administration of Ep?
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usually IV, orally ineffective
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what is a synthetic compound similar to Ep but able to be given orally?
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ephedrine
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metabolic actions of Ep?
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elevates blood glucose and lactate
insulin secretion inhibited |
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uses of Ep?
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vasoconstriction
bronchodilators cardiac stimulant |
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side effects of Ep?
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arrhythmias
palpitation angina headache cerebral hemorrhage |
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what sensitizes the myocardium to catecholamines?
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halothane
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actions of metaraminol?
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alpha 1 agonist
less potent than NorEP, but longer action sustained rise in BP |
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actions of phenylephrine?
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alpha 1 agonist
increase BP by vasoconstriction no oral nasal decongestant widens pupil without lens action |
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actions of alpha-methyldopa?
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alpha 2 agonist
reduction in BP and HR used in hypertensive pregnant women |
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what drug is used in hypertensive pregnant women?
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alpha-methyldopa
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actions of clonidine?
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initial rise in BP, overcome by alpha 2 receptor decrease in BP
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action of guanabenz?
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decrease in sympathetic outflow at vasomotor center
lowers BP |
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action of phenoxybenzamine?
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non-competitive alpha antagonist
excitatory response of smooth mm and exocrine glands antagonized used in peripheral vascular disease to stop vasospasm |
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action of phentolamine?
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competitive alpha blocker
stimulant action on GI and heart used in diagnosis of adrenal tumor-big drop in BP if Ep is in high concentration |
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actions of prazosin,doxazosin,terazosin,tamsulosin?
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alpha 1 blocker
decrease arterial P by lowering tone antihypertensive agents |
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action of isoproterenol?
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beta agonist
decrease in BP with rise in HR increase CO relaxes smooth mm causes hyperglycemia,lipolysis,insulin secretion,bronchodilation, cardiac stimulation |
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action of dopamine?
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beta 1 agonist
mesenteric and renal vasodilation increase GFR,urine flow,Na secretion,CO used in shock to increase renal function |
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action of dobutamine?
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beta 1 agonist
increases myocardial contractility and SV short-term treatment of congestive heart failure and to avoid hypertension |
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action of albuterol?
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beta 2 agonist
relax bronchial mm, uterus, skeletal mm supply less action on heart |
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action of salmeterol?
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most selective beta 2 agonist
lipid soluble and long duration of action |
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action of ritodrine?
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beta 2 agonist
management of premature labor- causes vasodilation and myometrial relaxation |
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action of propranolol?
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beta blocker
used in hypertension, arrhythmia,angina pectoris and migraines caution: augments hypoglycemia and blocks symptoms |
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action of pindolol?
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beta antagonist with intrinsic sympathomimetic activity
exacerbation of angina,less likely to get ME or arrhythmia upon withdrawl |
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action of timolol?
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beta antagonist
management of hypertension and angina pectoris prevention of reinfarction and death after initial MI |
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action of labetalol?
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alpha 1, beta 1,2 antagonist
treats hypertension |
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action of carvedilol?
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alpha 1, beta 1,2 antagonist
used in congestive heart failure |
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action of metoprolol?
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beta 1 antagonist
no action against beta 2 reduces plasma renin activity treats hypertension in patients with asthma, diabetes or peripheral vascular disease prevents second MI not advisable in congestive heart failure |
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action of atenolol?
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beta 1 antagonist
long half life used daily for hypertension |
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action of acebutolol?
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beta 1 antagonist
sympathomimetic activity |
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where are muscarinic receptors found?
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on effector cells
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where are nicotinic receptors found?
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ganglion and skeletal muscle NMJ
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what signaling system do muscarinic receptors use?
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G-protein linked
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what signaling system do nicotinic receptors use?
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ion channel
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where are muscarinic receptors located?
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cells of CNS
organs with parasym. innervation tissues innervated by postganglionic sympathetic cholinergic nerves |
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where are nicotinic receptors found?
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postganglionic cells in all autonomic ganglia
muscles innervated by somatic motor fibers some CNS neurons |
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what is the transmitter at both muscarinic and nicotinic receptors?
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AcH
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miosis
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pupillary constriction
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muscarinic agonist effect on the eye?
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smooth mm. contraction of iris sphincter resulting in pupillary constriction
smooth mm. contraction of the ciliary mm resulting in accommodation and draining of the aqueous humor |
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muscarinic agonist effect on the CV system?
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reduction in peripheral vascular resistance
slow pacemaker rate vasodilation |
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muscarinic agonist effect on the respiratory system?
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smooth mm. contraction of the bronchial tree
secretion stimulated in mucosa |
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muscarinic agonist effect on the GI?
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increases secretion and motility
relaxation of sphincters |
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muscarinic agonist effect on the urinary bladder?
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contraction of detrusor muscle
relaxation of the trigone and sphincter mm. promotes voiding |
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muscarinic agonist effect on glands?
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stimulate secretion in sweat, lacrimal and nasopharyngeal glands
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muscarinic effect on the veins?
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no influence
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muscarinic effect on the arterioles?
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dilation
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what muscarinic receptors are in the heart?
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M2
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mechanism of M2 action in the heart?
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open K channels
inhibit adenylyl cyclase |
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mechanism of M3 action in the smooth mm and exocrine glands?
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IP3 and DAG
increase cell Ca |
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mechanism of action of vascular smooth mm and GI?
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NO
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mechanism of action of Nm at the NMJ?
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depolarization of end plate-increase in permeability to K and Na
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effects of nicotine on the CV?
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sympathomimetic-hypertension
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effects of nicotine in the GI and urinary system?
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parasympathomimetic-nausea,vomiting, diarrhea and voiding
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effect of nicotinic agonist at the adrenal medulla?
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Ep secretion
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effect of nicotinic agonist at sympathetic and para ganglia?
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activation of post-ganglionic neurons
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effect of nicotinic agonist at the NMJ?
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skeletal mm. contraction
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use and action of bethanechol?
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muscarinic agonist
contraction of bladder and GI tract useful in abdominal distension, gastric atony and adynamic ileus |
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use of carbachol?
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muscarinic agonist
glaucoma, GI tract and urinary retention |
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use of methacholine?
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muscarinic agonist
diagnostic for bronchiolar hyperactivity- asthma |
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use of muscarine?
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found in mushromms and used to describe selective muscarinic sites
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action and use of pilocarpine?
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muscarinic agonist
treat open angle glaucoma and produces miosis contracts ciliary body and unblocks the trabeculae allowing fluid drainage |
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list muscarinic antagonists
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atropine and scopolamine
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action of atropine and scopolamine?
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competitive antagonists of Ach at muscarinic receptors
used in cases of hyperactive cholinergic systems reverse chemical toxicities |
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kinetics of atropine and scopolamine?
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tertiary amines-cross membranes
sedation CNS-movement disorders motion sickness |
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signs of muscarinic antagonist toxicity?
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hyperthemia-no sweating
red skin-vasodilatin dry mouth blurred vision hallucinations constipation |
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uses of muscarinic antagonists?
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mydriasis and paralysis of accommodation
prevent or reverse bradycardia and salivation decrease gut motility if spastic bronchodilator anti-motion sickness CNS movement disorders |
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use of NMJ blockers?
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muscle relaxation during surgery
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where do ganglionic blockers work?
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at all ganglia blocking both sym. and para. systems
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what is the major use for ganglionic blockers?
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short-term control of BP
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list some ganglionic agonists
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Ach, anti-cholinesterase,nicotine
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list some ganglionic blockers
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mecamylamine
trimethaphan |
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action and use of mecamylamine?
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competitive antagonist of Ach
lowers BP |
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side effects of mecamylamine?
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tremors, sedation, metal aberration
cycloplegia and mydriasis hypotension increased CO blocked reflexive BP control constipation urinary retention male sexual fx. depressed |
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foundation of BP control?
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persistent sympathetic activity releasing NorEp and the alpha1 receptor
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effect of ganglionic blocker on eye?
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mydriasis and cycloplegia
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effect of ganglionic blocker on HR?
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tachycardia
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effect of ganglionic blocker on ventricular contractility?
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decrease CO
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effect of ganglionic blocker on arterioles and veins?
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vasodilation of arterioles
dilation, pooling, decreased return and CO of veins |
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effect of ganglionic blockers on the GI?
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decreased tone, motility
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effect of ganglionic blockers on the urinary bladder?
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retention
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effect of ganglionic blockers on salivary glands?
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xerostomia- dry mouth, decrease secretion
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effect of ganglionic blockers on sweat glands?
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anhidrosis-no sweating
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list the anticholinesterases?
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neostigmine- useful duration
pyridostigmine- useful duration edrophonium-short action physostigmine-useful duration echothiophate-long duration |
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which of the anticholinesterases have direct agonist action at the NMJ?
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neostigmine
pyridostigmine |
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which amine of the anticholinesterases is tertiary and can enter the CNS?
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physostigmine- antidote for atropine poisoning
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name the organophosphate anticholinesterases
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echothiphate and sarin-lipid soluble and go everywhere
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uses of anticholinesterases?
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glaucoma
reversal of NMJ blockade myasthenia gravis improve GI and airway fx. cardiac arrhythmia reversal |
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toxicity of anticholinesterases?
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mostly sarin-most potent synthetic toxic agent known
high lipid solubility, low weight and volatility absorbed in cornea, lung and skin |
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signs of sarin toxicity
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initial-miosis, pain,blurred vision,wheezing,tightness
severe- salivation,sweating,urination and defecation,cramps,nausea,twitching,cramping,increase HR,TPR,ataxia,slurred speech, loss of reflex, paralysis |
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treatment of anticholinesterase toxicity
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atropine-against muscarinic activity
pralidoxime- cholinesterase reactivator ventilation and airway, shock treatment and convulsion prevention |
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muscarinic and nicotinic locations in the CNS?
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more muscarinic in brain
more nicotinic in spinal cord |
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affinity of nicotine in skeletal vs. neuronal receptors?
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neuronal
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mechanism of M1,3,5 receptors?
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IP3 to increase Ca
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mechanism of M2,4 receptors?
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open K channels
inhibit adenylyl cyclase activity |
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mechanism of nicotinic receptors?
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open Na/K channels
depolorization |
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how does the heart escape complete shut down from Ach action at M2 receptors?
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purkinje fibers in the ventricles-no effect by PNS
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what anticholinesterases act directly at the NMJ?
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neostigmine
pyridostigmine edrophonium diagnostic of myasthenia gravis reverse curare-competitive antagonist of Ach at NMJ |
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what causes arteriole dilation and sphincter relaxation at M2 receptors?
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NO
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what happens in toxicity of pilocarpine?
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over accommodation- near vision
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