CVS Practice Test 2025 - Free CVS Practice Questions and Study Guide

M2 receptors are a subtype of muscarinic acetylcholine receptors primarily found in the heart. When activated, they exert a negative influence on cardiac function, which aligns with the given choice that indicates negative effects on chronotropy, dromotropy, and inotropy.

Chronotropy refers to the heart rate, and activation of M2 receptors slows down the heart rate by inhibiting the pacemaker activity of the sinoatrial (SA) node.

Dromotropy involves the conduction velocity through the heart's conduction system, particularly the atrioventricular (AV) node. M2 receptor activation slows down conduction, again demonstrating a negative effect.

Inotropy refers to the contractile strength of the heart muscle. M2 activation leads to a decrease in the force of myocardial contraction, indicating a negative inotropic effect as well.

Understanding the role of M2 receptors is crucial in pharmacology and cardiology, as medications that interact with these receptors can significantly impact heart function. In contrast, the other choices either suggest an enhancement of heart functionalities or disregard the impact on either individual or multiple aspects of cardiac function, which does not accurately represent the physiological actions of M2 receptor activation.