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76 Cards in this Set

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  • Back
What is norepinephrine's precursor?
What is norepinephrine metabolized by?
Monoamine Oxidase (MAO)
Vesicles are how norepinephrine is stored at terminal bouton. What agent blocks aggregation of norepinephrine into vesicles?
What agents block the release of NE into the synaptic cleft?
Guanethidine, bretylium
By what mechanism at the level of neuron does cocaine achieve it's effects?
Cocaine (among other agents) blocks norepinephrine reuptake at the synaptic cleft.
Which adrenergic receptor can be stimulated to block further release of NE?
What do alpha-1 receptor second messengers effect?
Activate phospholipase C, increase IP3 and intracellular Ca
What do alpha-2 receptor second messengers effect?
Inhibit adenylyl cyclase and decrease cAMP.
What do beta-1/2 receptor second messengers accomplish in myocardial cells?
Stimulate adenylyl cyclase and increase cAMP
How reactive are adrenergic receptors to epinephrine vs. norepinephrine?
Epinephrine causes a greater reaction in alpha-1,2, and especially beta-2 receptors.

There is no difference in reactivity for beta-1 receptors.
What are the effects of beta-1 (and some 2) stimulation on the heart at the level of nodes, HIS bundle and myocardium?
SA node: increase HR
AV node: increase conduction speed
HIS: increase conduction speed AND automaticity
Myocard: increase contractility
What are the effects of beta-1 stimulation on the kidneys?
Increase renin secretion, which activates angiotensin and aldosterone, constricting vessels and increasing reabsorption of water.
What are the effects of beta-2 stimulation on smooth muscle?
Relaxation (countered in arterioles by alpha-1 and angiotensin), including ciliary muscles, enabling distance vision.
What are the effects of beta-2 stimulation on skeletal muscle?
Increase K uptake
What are the metabolic effects of beta-2 stimulation?
Increase glycogenolysis and insulin secretion.
What are the effects of alpha-1 stimulation on smooth muscle (not intestine)?
Contraction (helped by angiotensin, countered by beta-2).
What are the effects of alpha-1 stimulation on intestine?
Relaxation! Remember that cholinergic (parasympathetic) system is for resting and digesting. Sympathetic stimulation will let sleeping guts lie.
What are the effects of alpha-1 stimulation on the eye?
Radial muscle contracts
Lacrimal glands secrete tears.
What are the metabolic effects of alpha-1 stimulation?
Increase glycogenolysis.
What are the effects of alpha-1 stimulation on the kidney?
Decrease renin secretion (counteract beta-1 stimulation)
What are the effects of alpha-2 stimulation? There were only 2 stated.
Pancreas: Decrease insulin secretion (counteract beta-2 stimulation) and decrease release of NE.
Which of the following does NOT result from stimulation of beta receptors by epinephrine?

Increased HR
Increased glycogenolysis
Arteriolar vasoconstriction
Intestinal muscle relaxation
Arteriolar vasoconstriction - this is achieved by alpha-1 stimulation.
If you were to design a drug for pheochromocytoma, what would be it's mechanism of action?
alpha, then beta blockade (beta blockers would result in unopposed alpha stimulation, causing possibly lethal hypertension due to vasoconstriction)
From what enzyme and precursors are ACh synthesized?
Choline acetyltransferase, using choline and acetyl coA
What agent reduces choline uptake into postganglionic ACh producing cells?
What agent inhibits ACh storage in vesicles?
What agent inhibits ACh's release at the synaptic cleft?
Botulinum toxin
How is ACh removed from the syaptic cleft?
AChE - removes, but reuptake is minimal
Which receptors (nicotinic vs. muscarinic) are quicker to respond?
What are the effects of muscarinic receptors via 2nd messengers?
M1,3,5 - increase intracellular Ca and protein phosphorylation
M2,4 - increase K permeability and decrease cAMP (just like alpha-2)
Where are M2 receptors located?
SA and AV nodes, atria and ventricles
What are the effects of M2 stimulation?
SLOWS CONDUCTION via: Increased potassium permeability (inhibitory effect)
Decreases adenylyl cyclase activity (less cAMP)
Decreased Ca permeability
Where are M3 receptors located?
Smooth muscle: sphincters, vessels, glands
What are the effects of M3 stimulation
Relaxation of blood vessels (when endothelium intact) via endothelial NO release. Relaxation of sphincters, increased gland secretions
What are the effects of muscarinic stimulation on the heart and vascular smooth muscle?
SA: Lower heart rate
AV: slowed conduction
Myocardium: Lower contractility
Vasc smooth muscle: relaxation
What cranial nerve is responsible for cardiac muscarinic stimulation?
CN X: Vagus
What are the effects of muscarinic stimulation outside of the heart/vascular system?
Contraction of GI/bronchiolar, eye muscles;
Relaxation of urinary/GI sphincters;
Increased gland production
What are the effects of epinephrine?
HEART beta-1: increased chronotropic (SA), dromotropic (AV), and inotropic (contractility) effects
VASC: alpha-1 increases @ high doses, beta-2 decreases at low doses
BRONCH: beta-2 dilates
What are the effects of norepinephrine?
alpha-1, beta-1 agonist.

SIGNIFICANT bp and contractility (inotropy) increase, because no beta-2 vasodilation like with epinephrine.
What would you expect to see if you administered epinephrine IV into an elderly patient for heart failure, and due to his brittle veins, noticed that some of the IV fluid had leaked into the surrounding tissue?
Significant necrosis can be expected from any alpha-1 agonist if it extravasates from IV administration
What is the precursor of norepinephrine?
Which adrenergic receptors does dopamine stimulate?
alpha-1, beta-1;

Also stimulates d-1 receptors, dilating mesenteric, renal and coronary vasculature
What are the dose-dependent effects of dopamine?
Low (1-2mcg/kg/min): renal/mesenteric vasodilation
Medium (5-10 mcg/kg/min): increased chronotropy, inotropy (HR, contractility)
High (10-20 mcg/kg/min): inc vasoconstriction, chronotropy, inotropy
What drug can you administer in low doses to improve renal function?
What drug (from the list) is used in cardiogenic shock to increase inotropy rather than peripheral resistance?
dobutamine (also isoproterenol, but more likely to cause reflex tach)
What drug (from the list) used as a nasal decongestant can cause significant alpha-1 stimulation, raising blood pressure and risk of stroke?
pseudoephedrine (also ephedrine and phenylpropanolamine, but both FDA banned)
What beta-2 agonist is used in rescue inhalers for asthma?
What results from beta-1 overstimulation?
Tachycardia, increased myocardial O2 demand, arrhythmia, cardiac damage
What is a risk of intermittant beta-1 agonist infusion for decompensated heart failure?
Increased overall mortality
What results from beta-2 (respiratory) overstimulation?
skeletal muscle tremors, tachycardia, arrhythmias, hypokalemia
What results from alpha-1 overstimulation?
severe BP elevation, increasing myocardial O2 demand, predisposing to stroke and cardiac damage
What are alpha blockers used for?
HBP (relaxes vascular smooth muscle), BPH (improves urinary flow)
What is a side effect of alpha-1 blockade?
Orthostatic hypotension or syncope with first or increase in doses
What alpha blockers are used for blood pressure control?
block a-1 =SIN
prazosin, terazosin, doxazosin
What alpha blocker is used for BPH to improve urine flow>
tamsulosin - blocks a-1a subtype, specific to prostate
What would a combined alpha-1/2 blockade (ex: phentolamine) be useful in treating?
What are adverse events from combined alpha-1/2 blockade (e.g., phentolamine)?
severe hypotension causing reflex tachycardia, arrhythmias and myocardial ischemia
How can you achieve selective beta-blockade (without blocking other adrenergic receptors)?
It's dose dependent: higher doses mean lost selectivity
What intrinsic property of some beta-blockers is less useful in treating ischemic heart disease?
intrinsic sympathomimetic activity that occurs with low sympathetic tone (agonism as well as blockade)
What are beta blockers used for?
HBP, Ischemic heart disease, systolic heart failure, arrhythmias

Also Glaucoma, Thyroid storm, stage fright and migraine prevention
What are adverse effects of beta blocker use?
Decompensated systolic heart failure, AV block, sinus bradycardia, bronchoconstriction, lowered HDL, difficult to identify hypoglycemia in DM, peripheral vasoconstriction, nightmares and sedation
How do parasympathomimetics work?
Stimulate muscarinic receptors (direct) , OR inhibig AChE (indirect)
What are the representative beta blockers we need to know for this exam?
beta blockers = LOL
What class are the following medications?

Direct-acting muscarinic agonists (parasympathomimetics)
What is pilocarpine indicated for?
Xerostomia (permanent dry mouth) and glaucoma
What is bethanechol used for?
gastroparesis and urinary retention in patients without obstruction
In what class are the following?

Organophosphate pesticides
Indirect-acting muscarinic agonists (parasympathomimetics), which act to block AChE
What are indirect-acting parasympathetic agonists used for?
Myasthenia gravis (-stigmines, to increase AChE at NMJ)
Alzheimers (Donepezil)
Counteract nerve gas or antimuscarinic poisoning
Other conditions benefited by direct-acting agents (glaucoma, xerostomia, gastroparesis)
Adverse effects of muscarinic agonists
Bradycardia, hypotension, bronchoconstriction, GI distress and increased acid secretion
What agent can you prescribe for organophosphate (muscarinic agonist) poisoning?
pralidoxime (2-PAM) reactivates cholinesterase
*Also respiratory support
What are the effects of antimuscarinic drugs?
Cause the following:

Increased HR, conduction velocity through AV node, block of reflex bradycardia, bronchodilation, reduced lung secretions, inhibit GI/GU tone, dilated pupils, cycloplegia, lowered sweat and dry mouth
What antimuscarinic drug is used for significant bradycardia?
What antimuscarinic drug is used for motion sickness?
What antimuscarinic drugs are useful in Parkinson's because they improve the effects of relative cholinergic excess?
Benztropine and trihexylphenidyl
What effect does oxybutynin (Ditropan) have on the urinary tract?
Antispasmodic for overactive bladder.
What condition is ipratropium used to treat?
COPD - administered via aerosol, does not cross BBB and has low systemic absorption