Which of the Following is Most Apt to Induce an Autonomically

Question

Which of the following is most apt to induce an autonomically induced bradycardia?
A) Secretion of norepinephrine by the postganglionic adrenergic fibers
B) Activation of the beta1-adrenergic receptors
C) Activation of the muscarinic receptors
D) Sympathetic nerve stimulation

Accepted Answer

Activation of the muscarinic receptors, specifically the M2 subtype, will induce a bradycardia through the inhibition of the sinoatrial node and decrease in heart rate. This response is mediated by the parasympathetic nervous system.