MCQ Quiz: Pharmacology of Autonomic Function

Welcome, PharmD students, to this foundational MCQ quiz on the Pharmacology of Autonomic Function! The autonomic nervous system (ANS) regulates vital involuntary bodily functions, and drugs targeting its cholinergic and adrenergic pathways are among the most widely used in medicine. This quiz will test your understanding of neurotransmitters, receptors, and the mechanisms, therapeutic uses, and adverse effects of key sympathomimetic, sympatholytic, parasympathomimetic, and parasympatholytic drugs. Let’s explore how these agents modulate autonomic control!

1. The two main divisions of the autonomic nervous system (ANS) are the:

• a) Somatic and Sensory nervous systems.
• b) Sympathetic and Parasympathetic nervous systems.
• c) Central and Peripheral nervous systems.
• d) Afferent and Efferent nervous systems.

Answer: b) Sympathetic and Parasympathetic nervous systems.

2. The primary neurotransmitter released by postganglionic parasympathetic neurons is:

• a) Norepinephrine
• b) Epinephrine
• c) Acetylcholine (ACh)
• d) Dopamine

Answer: c) Acetylcholine (ACh)

3. Most postganglionic sympathetic neurons release which neurotransmitter?

• a) Acetylcholine (ACh)
• b) Serotonin
• c) Norepinephrine (NE)
• d) GABA

Answer: c) Norepinephrine (NE)

4. Muscarinic receptors (M1-M5) are a type of _______ receptor, primarily found at _______ neuroeffector junctions.

• a) adrenergic; sympathetic
• b) cholinergic; parasympathetic
• c) dopaminergic; central
• d) nicotinic; somatic

Answer: b) cholinergic; parasympathetic

5. Adrenergic receptors are classified into alpha (α) and beta (β) subtypes. Which of the following is a primary effect of stimulating β1-adrenergic receptors?

• a) Bronchodilation
• b) Vasoconstriction of peripheral arterioles
• c) Increased heart rate and contractility
• d) Uterine relaxation

Answer: c) Increased heart rate and contractility

6. Pilocarpine and bethanechol are examples of _______ cholinergic agonists, meaning they directly bind to and activate cholinergic receptors.

• a) indirect-acting
• b) direct-acting
• c) irreversible
• d) non-selective adrenergic

Answer: b) direct-acting

7. Neostigmine and physostigmine are indirect-acting cholinergic agonists (cholinesterase inhibitors) that work by:

• a) Directly stimulating muscarinic receptors.
• b) Inhibiting the enzyme acetylcholinesterase, thereby increasing the concentration and duration of action of ACh at the synaptic cleft.
• c) Blocking nicotinic receptors.
• d) Increasing the synthesis of acetylcholine.

Answer: b) Inhibiting the enzyme acetylcholinesterase, thereby increasing the concentration and duration of action of ACh at the synaptic cleft.

8. Atropine is a prototypical antimuscarinic (anticholinergic) drug. Its pharmacological effects include all of the following EXCEPT:

• a) Tachycardia
• b) Mydriasis (pupil dilation) and cycloplegia
• c) Increased salivation, lacrimation, and bronchial secretions
• d) Decreased GI motility and urinary retention

Answer: c) Increased salivation, lacrimation, and bronchial secretions (Atropine causes dryness – “dry as a bone”).

9. Ipratropium and tiotropium are quaternary ammonium antimuscarinic agents primarily used in the treatment of COPD and asthma due to their ability to cause:

• a) Systemic anticholinergic effects.
• b) Bronchodilation with minimal systemic absorption when inhaled.
• c) Potent vasoconstriction.
• d) Increased mucus secretion.

Answer: b) Bronchodilation with minimal systemic absorption when inhaled.

10. Succinylcholine is a depolarizing neuromuscular blocker that initially causes muscle fasciculations followed by flaccid paralysis. Its action is terminated by:

• a) Acetylcholinesterase
• b) Plasma pseudocholinesterase (butyrylcholinesterase)
• c) Renal excretion unchanged
• d) Hepatic metabolism via CYP450

Answer: b) Plasma pseudocholinesterase (butyrylcholinesterase)

11. Phenylephrine is a selective _______ agonist primarily used as a nasal decongestant and vasopressor.

• a) Alpha-1 adrenergic
• b) Alpha-2 adrenergic
• c) Beta-1 adrenergic
• d) Beta-2 adrenergic

Answer: a) Alpha-1 adrenergic

12. Clonidine is a centrally acting antihypertensive drug that stimulates _______ receptors in the brainstem, leading to reduced sympathetic outflow.

• a) Alpha-1 adrenergic
• b) Alpha-2 adrenergic
• c) Beta-1 adrenergic
• d) Dopamine D1

Answer: b) Alpha-2 adrenergic

13. Albuterol and salmeterol are selective _______ agonists used as bronchodilators in asthma and COPD.

• a) Alpha-1 adrenergic
• b) Alpha-2 adrenergic
• c) Beta-1 adrenergic
• d) Beta-2 adrenergic

Answer: d) Beta-2 adrenergic

14. Dobutamine is a synthetic catecholamine that is a relatively selective _______ agonist, primarily used to increase cardiac output in acute heart failure.

• a) Alpha-1 adrenergic
• b) Alpha-2 adrenergic
• c) Beta-1 adrenergic
• d) Beta-2 adrenergic

Answer: c) Beta-1 adrenergic

15. Epinephrine is a non-selective adrenergic agonist that stimulates alpha-1, alpha-2, beta-1, and beta-2 receptors. At low doses, its _______ effects often predominate, while at high doses, _______ effects become more pronounced.

• a) alpha; beta
• b) beta (especially β2 vasodilation); alpha (vasoconstriction)
• c) muscarinic; nicotinic
• d) dopaminergic; serotonergic

Answer: b) beta (especially β2 vasodilation); alpha (vasoconstriction)

16. Prazosin, doxazosin, and terazosin are selective _______ antagonists used for hypertension and benign prostatic hyperplasia (BPH).

• a) Alpha-1 adrenergic
• b) Alpha-2 adrenergic
• c) Beta-1 adrenergic
• d) Non-selective beta

Answer: a) Alpha-1 adrenergic

17. Propranolol is a non-selective beta-blocker, meaning it blocks both β1 and β2 adrenergic receptors. A potential adverse effect in patients with asthma due to β2 blockade is:

• a) Tachycardia
• b) Bronchodilation
• c) Bronchoconstriction
• d) Hypertension

Answer: c) Bronchoconstriction

18. Metoprolol and atenolol are examples of _______ beta-blockers, which are preferred in patients with asthma or COPD if a beta-blocker is indicated.

• a) non-selective
• b) cardioselective (β1-selective)
• c) alpha-1 selective
• d) mixed alpha and beta

Answer: b) cardioselective (β1-selective)

19. Labetalol and carvedilol are unique beta-blockers because they also possess _______ blocking activity, leading to vasodilation.

• a) Alpha-2 adrenergic
• b) Muscarinic cholinergic
• c) Alpha-1 adrenergic
• d) Dopamine D2

Answer: c) Alpha-1 adrenergic

20. The “SLUDGE” syndrome (Salivation, Lacrimation, Urination, Defecation, GI distress, Emesis) and miosis are characteristic signs of toxicity from overstimulation of which receptors, often due to cholinesterase inhibitor poisoning?

• a) Adrenergic alpha receptors
• b) Adrenergic beta receptors
• c) Muscarinic cholinergic receptors
• d) Nicotinic neuronal receptors

Answer: c) Muscarinic cholinergic receptors

21. Pralidoxime (2-PAM) is an antidote used in organophosphate (irreversible cholinesterase inhibitor) poisoning. It works by:

• a) Directly blocking muscarinic receptors.
• b) Reactivating acetylcholinesterase by cleaving the phosphate group from the enzyme, if administered before “aging” occurs.
• c) Increasing the synthesis of acetylcholine.
• d) Blocking nicotinic receptors at the neuromuscular junction.

Answer: b) Reactivating acetylcholinesterase by cleaving the phosphate group from the enzyme, if administered before “aging” occurs.

22. Oxybutynin and tolterodine are antimuscarinic agents primarily used for the treatment of:

• a) Glaucoma
• b) Myasthenia gravis
• c) Overactive bladder (OAB) with symptoms of urinary urgency, frequency, and urge incontinence.
• d) Parkinson’s disease

Answer: c) Overactive bladder (OAB) with symptoms of urinary urgency, frequency, and urge incontinence.

23. Non-depolarizing neuromuscular blockers (e.g., rocuronium, vecuronium) cause skeletal muscle relaxation by:

• a) Activating nicotinic receptors at the neuromuscular junction, leading to persistent depolarization.
• b) Competitively antagonizing acetylcholine at nicotinic (Nm) receptors at the neuromuscular junction.
• c) Inhibiting acetylcholinesterase.
• d) Blocking muscarinic receptors in skeletal muscle.

Answer: b) Competitively antagonizing acetylcholine at nicotinic (Nm) receptors at the neuromuscular junction.

24. Amphetamine and tyramine are indirect-acting sympathomimetics that cause their effects primarily by:

• a) Directly stimulating adrenergic receptors.
• b) Promoting the release of stored norepinephrine from sympathetic nerve terminals.
• c) Inhibiting the reuptake of acetylcholine.
• d) Blocking MAO enzyme only.

Answer: b) Promoting the release of stored norepinephrine from sympathetic nerve terminals.

25. The therapeutic effect of donepezil and rivastigmine in Alzheimer’s disease is based on their ability to:

• a) Stimulate adrenergic receptors in the brain.
• b) Inhibit acetylcholinesterase in the CNS, thereby increasing acetylcholine levels.
• c) Block dopamine receptors.
• d) Enhance GABAergic transmission.

Answer: b) Inhibit acetylcholinesterase in the CNS, thereby increasing acetylcholine levels.

26. Which of the following is a primary pharmacological effect of activating α2-adrenergic receptors in the presynaptic neuron?

• a) Increased release of norepinephrine.
• b) Decreased release of norepinephrine (negative feedback).
• c) Increased release of acetylcholine.
• d) Vasoconstriction of arterioles.

Answer: b) Decreased release of norepinephrine (negative feedback).

27. Tamsulosin is an alpha-1 antagonist that is relatively selective for α1A receptors found in the prostate and bladder neck, making it useful for:

• a) Treating hypertension with less orthostatic hypotension than non-selective alpha-1 blockers.
• b) Improving symptoms of benign prostatic hyperplasia (BPH) with less impact on blood pressure.
• c) Causing significant bronchoconstriction.
• d) Treating narcolepsy.

Answer: b) Improving symptoms of benign prostatic hyperplasia (BPH) with less impact on blood pressure.

28. The main difference between “direct-acting” and “indirect-acting” cholinomimetics is that direct-acting drugs _______, while indirect-acting drugs _______.

• a) block ACh receptors; stimulate ACh receptors
• b) bind directly to and activate cholinoceptors; increase ACh levels by inhibiting acetylcholinesterase
• c) inhibit acetylcholinesterase; bind to cholinoceptors
• d) are natural alkaloids; are synthetic esters

Answer: b) bind directly to and activate cholinoceptors; increase ACh levels by inhibiting acetylcholinesterase

29. Isoproterenol is a non-selective beta-adrenergic agonist. Its effects would include:

• a) Increased heart rate (β1) and bronchodilation (β2).
• b) Vasoconstriction (α1) and decreased heart rate.
• c) Only bronchodilation.
• d) Only increased heart rate.

Answer: a) Increased heart rate (β1) and bronchodilation (β2).

30. The “fight or flight” response is mediated primarily by the _______ nervous system, with _______ as a key neurotransmitter/hormone.

• a) parasympathetic; acetylcholine
• b) sympathetic; norepinephrine and epinephrine
• c) somatic; dopamine
• d) enteric; serotonin

Answer: b) sympathetic; norepinephrine and epinephrine

31. A common adverse effect of beta-2 agonists like albuterol, when used for asthma, is:

• a) Bradycardia
• b) Tremor, nervousness, and tachycardia (due to some β1 spillover or reflex effects).
• c) Bronchoconstriction
• d) Severe hypertension

Answer: b) Tremor, nervousness, and tachycardia (due to some β1 spillover or reflex effects).

32. Drugs that block ganglionic nicotinic (Nn) receptors (ganglionic blockers) would affect:

• a) Only parasympathetic ganglia.
• b) Only sympathetic ganglia.
• c) Both parasympathetic and sympathetic ganglia, leading to complex and often widespread effects.
• d) Only the neuromuscular junction.

Answer: c) Both parasympathetic and sympathetic ganglia, leading to complex and often widespread effects.

33. Which of the following is a key therapeutic use for muscarinic agonists like pilocarpine or bethanechol?

• a) Treatment of bradycardia.
• b) Relief of urinary retention (bethanechol) or treatment of glaucoma/xerostomia (pilocarpine).
• c) Management of asthma.
• d) Treatment of hypertension.

Answer: b) Relief of urinary retention (bethanechol) or treatment of glaucoma/xerostomia (pilocarpine).

34. One of the “cardinal” signs of atropine (muscarinic antagonist) overdose is:

• a) Miosis (pupil constriction).
• b) Profuse salivation.
• c) Tachycardia, mydriasis, dry mouth, flushed skin, delirium (“red as a beet, dry as a bone, blind as a bat, mad as a hatter, hot as a hare”).
• d) Bradycardia and hypotension.

Answer: c) Tachycardia, mydriasis, dry mouth, flushed skin, delirium (“red as a beet, dry as a bone, blind as a bat, mad as a hatter, hot as a hare”).

35. The pharmacological action of dopamine as a vasopressor is dose-dependent. At low doses, it primarily stimulates D1 receptors causing renal vasodilation; at moderate doses, it stimulates _______ receptors; and at high doses, it stimulates _______ receptors.

• a) alpha; beta
• b) beta-1; alpha-1
• c) muscarinic; nicotinic
• d) serotonin; histamine

Answer: b) beta-1 (increasing contractility/HR); alpha-1 (causing vasoconstriction)

36. Reserpine (a historically significant antihypertensive) depletes stores of norepinephrine, dopamine, and serotonin from nerve terminals by:

• a) Inhibiting their synthesis.
• b) Blocking their reuptake.
• c) Irreversibly inhibiting vesicular monoamine transporter (VMAT), preventing their storage in vesicles.
• d) Directly destroying the nerve terminals.

Answer: c) Irreversibly inhibiting vesicular monoamine transporter (VMAT), preventing their storage in vesicles.

37. The “intrinsic sympathomimetic activity” (ISA) of some beta-blockers (e.g., pindolol) means they:

• a) Also block alpha receptors.
• b) Act as partial agonists at beta-receptors, causing less resting bradycardia or bronchoconstriction than pure antagonists.
• c) Are more potent than non-ISA beta-blockers.
• d) Are only effective when sympathetic tone is very high.

Answer: b) Act as partial agonists at beta-receptors, causing less resting bradycardia or bronchoconstriction than pure antagonists.

38. Ephedrine and pseudoephedrine are mixed-acting sympathomimetics because they:

• a) Only block adrenergic receptors.
• b) Both directly stimulate adrenergic receptors and enhance the release of norepinephrine from nerve terminals.
• c) Only inhibit norepinephrine reuptake.
• d) Only stimulate cholinergic receptors.

Answer: b) Both directly stimulate adrenergic receptors and enhance the release of norepinephrine from nerve terminals.

39. The primary therapeutic effect of alpha-1 adrenergic antagonists in benign prostatic hyperplasia (BPH) is:

• a) To shrink the prostate gland.
• b) To relax smooth muscle in the bladder neck and prostate, improving urinary flow.
• c) To inhibit testosterone production.
• d) To increase bladder contractility.

Answer: b) To relax smooth muscle in the bladder neck and prostate, improving urinary flow.

40. A common side effect of centrally acting alpha-2 agonists like clonidine is:

• a) Insomnia and agitation.
• b) Sedation, dry mouth, and constipation.
• c) Tachycardia and hypertension.
• d) Increased salivation.

Answer: b) Sedation, dry mouth, and constipation.

41. From a pharmacology perspective, the “selectivity” of a drug for a specific receptor subtype (e.g., β1 vs. β2) is often:

• a) Absolute at all doses.
• b) Dose-dependent; selectivity may be lost at higher doses.
• c) Irrelevant to its clinical effects.
• d) Only determined by its route of administration.

Answer: b) Dose-dependent; selectivity may be lost at higher doses.

42. The primary indication for edrophonium, a short-acting reversible cholinesterase inhibitor, is:

• a) Long-term management of Alzheimer’s disease.
• b) Diagnosis of myasthenia gravis (Tensilon test).
• c) Treatment of organophosphate poisoning.
• d) Relief of urinary retention.

Answer: b) Diagnosis of myasthenia gravis (Tensilon test).

43. Which autonomic drug class is commonly used topically in ophthalmology to cause mydriasis (pupil dilation) for eye examinations?

• a) Beta-blockers (e.g., timolol)
• b) Muscarinic agonists (e.g., pilocarpine)
• c) Antimuscarinics (e.g., tropicamide, cyclopentolate) or Alpha-1 agonists (e.g., phenylephrine)
• d) Cholinesterase inhibitors

Answer: c) Antimuscarinics (e.g., tropicamide, cyclopentolate) or Alpha-1 agonists (e.g., phenylephrine)

44. The autonomic nervous system controls “involuntary” bodily functions. Which of these is primarily under ANS control?

• a) Lifting a weight.
• b) Regulation of heart rate and digestion.
• c) Writing an essay.
• d) Kicking a ball.

Answer: b) Regulation of heart rate and digestion.

45. The pharmacology of drugs acting on the ANS is based on their ability to mimic or block the actions of endogenous neurotransmitters like:

• a) Only serotonin and GABA.
• b) Acetylcholine and norepinephrine/epinephrine.
• c) Only histamine and prostaglandins.
• d) Only endorphins and enkephalins.

Answer: b) Acetylcholine and norepinephrine/epinephrine.

46. A patient with bradycardia might be treated with which type of autonomic drug to increase heart rate?

• a) A beta-blocker like propranolol.
• b) An antimuscarinic like atropine, or a beta-agonist like isoproterenol.
• c) A cholinesterase inhibitor like neostigmine.
• d) An alpha-1 antagonist like prazosin.

Answer: b) An antimuscarinic like atropine, or a beta-agonist like isoproterenol.

47. A key difference between the sympathetic and parasympathetic nervous systems is the typical length of their preganglionic and postganglionic fibers. The sympathetic system generally has _______ preganglionic and _______ postganglionic fibers.

• a) long; short
• b) short; long
• c) short; short
• d) long; long

Answer: b) short; long (PSNS is long preganglionic, short postganglionic).

48. The adrenal medulla is considered a modified sympathetic ganglion that releases primarily _______ into the bloodstream upon stimulation.

• a) Acetylcholine
• b) Norepinephrine
• c) Epinephrine (and some norepinephrine)
• d) Dopamine

Answer: c) Epinephrine (and some norepinephrine)

49. From a pharmacology standpoint, understanding the specific receptor subtypes targeted by an autonomic drug helps predict its:

• a) Cost and availability.
• b) Therapeutic effects and potential side effect profile.
• c) Color and taste.
• d) Manufacturing process.

Answer: b) Therapeutic effects and potential side effect profile.

50. The overall “tone” of most organs with dual ANS innervation (sympathetic and parasympathetic) is usually determined by:

• a) Only the sympathetic input.
• b) Only the parasympathetic input.
• c) A dynamic balance between sympathetic and parasympathetic activity, with one often being dominant for a particular function.
• d) Hormonal input from the thyroid gland.

Answer: c) A dynamic balance between sympathetic and parasympathetic activity, with one often being dominant for a particular function.