Adrenergic Neurotransmission Flashcards

Flashcards for reviewing adrenergic neurotransmission, including receptors, drugs, and clinical implications.

What is the major neurotransmitter of postganglionic sympathetic fibers?

Norepinephrine

Activation of α1​ receptors on blood vessels leads to what?

Vasoconstriction

Which enzyme is primarily responsible for the metabolism of norepinephrine and serotonin?

MAO-A

Epinephrine is a major hormone released from which gland?

Adrenal medulla

What is the primary effect of β1​ receptor stimulation on the heart?

Increased heart rate and contractility

Which drug increases the release of norepinephrine?

Amphetamine

Which is a direct sympathomimetic with primary action on α1​ receptors?

Phenylephrine

How is norepinephrine typically administered for septic shock?

Intravenous infusion

What is a common therapeutic use of selective β2​ agonists?

Asthma

Which adrenergic receptor, when activated, causes bronchodilation?

β2

Which sympathomimetic is considered life-saving for acute anaphylactic shock?

Epinephrine

Which drug inhibits vesicular uptake (Uptake III) of norepinephrine?

Reserpine

What is the primary mechanism of action for the antianginal effects of beta-blockers?

Decreasing myocardial oxygen demand

At low doses, dopamine primarily acts as an agonist on which receptors?

D1 receptors

Which adverse effect is commonly associated with β2​ agonists?

Skeletal muscle tremors

A patient with Parkinson's Disease might be treated with inhibitors of which enzyme?

COMT

Which beta-blocker is selective for β1​ receptors and releases Nitric Oxide?

Nebivolol

Which enzyme is the rate-limiting step in the synthesis of norepinephrine?

Tyrosine Hydroxylase

What is a common therapeutic use of α1​ agonists like Oxymetazoline?

Local nasal and eye decongestion

What is the effect of alpha-2 agonists on norepinephrine release?

Decrease release

Which beta-blocker crosses the blood-brain barrier and requires dose adjustment in liver diseases?

Propranolol

What is the clinical implication of increased Vanillylmandelic Acid (VMA) in 24-hour urine?

Diagnostic for pheochromocytoma

Which beta-blocker has Intrinsic Sympathomimetic Activity (ISA)?

Pindolol

Activation of which receptor leads to increased intracellular Ca2+ and smooth muscle contraction?

α1

What is the main difference in the effect of epinephrine and norepinephrine on diastolic blood pressure at clinical doses?

Epinephrine decreases DBP, Norepinephrine increases DBP

What is a likely therapeutic benefit of a medication that selectively blocks α1​ receptors in a male patient with hypertension and benign prostatic hyperplasia?

Improved urinary flow

Which drug likey be administered to a patient experiencing severe bradycardia and AV block?

Isoprotrenol

Epinephrine reversal unmasks the hypotensive effect mediated by which receptor?

β2

Which effect contributes to the antihypertensive effect of beta-blockers?

Decrease in peripheral NE release

What adrenergic antagonist is crucial to administer preoperatively to a patient with pheochromocytoma?

Nonselective α blocker (e.g., Phenoxybenzamine)

What adverse effect is most concerning for an asthmatic patient given a non-selective beta-blocker?

Bronchoconstriction

What is the clinical significance of a beta-blocker possessing Membrane Stabilizing Activity (MSA)?

It has higher antiarrhythmic effect.

What is true regarding the fate of released norepinephrine in the synapse?

The majority (90%) undergoes neuronal reuptake (Uptake I).

Which receptor is primarily activated by a sympathomimetic that causes vasoconstriction?

α1

How does the activation of central α2​ receptors affect NE release?

It leads to negative feedback by excess NE, decreasing its release.

A drug that is a D1​ agonist at low doses, β1​ agonist at moderate doses, and α1​ agonist at high doses is?

Dopamine

Which effect of beta-blockers might lead to increased coronary spasm in patients with vasospastic angina?

Unopposed α actions due to β2 blockade.

Which receptor is primarily responsible for gangrene at the injection site caused by a high dose of local anesthetic with epinephrine?

α1

Decreased blood pressure is caused by activation of which receptor?

α2

Which pharmacological action contributes to the antiarrhythmic effects of beta-blockers?

Blocking sympathetic activity in SAN and AVN

A new adrenergic agonist is most similar to which known drug?

Epinephrine

Which adverse effect might a patient experience from a lipophilic beta-blocker that crosses the BBB?

Depression

The primary receptor subtype of a drug that causes vasodilation of renal, coronary, cerebral, and mesenteric blood vessels is?

D1

The safest beta-blocker choice to minimize COPD exacerbation is?

Cardioselective β1​ blocker (e.g., Metoprolol)

What is the most likely consequence of a drug inhibiting the enzyme responsible for converting NE to EPI?

Decreased production of epinephrine in the adrenal medulla.

Which MAO enzyme type needs to be avoided in a patient undergoing therapy for depression?

MAO-A, Tyramine-containing foods

A drug blocks the reuptake of norepinephrine and inhibits vesicular uptake will lead to which overall net effect on sympathetic activity?

Initial increase followed by depletion and decreased activity

Activation of this receptor causes contraction of the prostate

Activation of this receptor causes contraction of the prostate.

A vital sign profile most consistent with continuous stimulation of β1​ and β2​ receptors is?

Increased Systolic BP, Decreased Diastolic BP, Direct Tachycardia.

What effect will specifically inhibit the non-neuronal uptake (Uptake II) of norepinephrine have on the overall fate of NE?

Increased action of NE due to reduced tissue uptake.