Which physiological effect is associated with muscarinic receptor activation in the heart?

Unlock all questions

This demo includes only 20 questions. Upgrade to access hundreds of questions, flashcards, exam simulations, and disable ads.

Full question bankExam simulationsFlashcards
From $9.99Unlock all

Prepare for the Drug Action 2 Exam. Focus on multiple-choice questions, learn through interactive quizzes, and understand core drug mechanisms with explanations. Dive deep into pharmacokinetics and pharmacodynamics to ace your test!

Multiple Choice

Which physiological effect is associated with muscarinic receptor activation in the heart?

Explanation:
Muscarinic receptor activation in the heart lowers heart rate through parasympathetic control. When acetylcholine binds M2 receptors on the SA node, they are Gi/o‑coupled, which reduces cAMP levels and lowers the pacemaker slope. The βγ subunits open GIRK potassium channels, causing hyperpolarization of pacemaker cells. Together, this slows automaticity in the SA node and slows conduction through the AV node, producing a decrease in heart rate (bradycardia). This contrasts with sympathetic activation, which raises heart rate by increasing cAMP and calcium currents.

Muscarinic receptor activation in the heart lowers heart rate through parasympathetic control. When acetylcholine binds M2 receptors on the SA node, they are Gi/o‑coupled, which reduces cAMP levels and lowers the pacemaker slope. The βγ subunits open GIRK potassium channels, causing hyperpolarization of pacemaker cells. Together, this slows automaticity in the SA node and slows conduction through the AV node, producing a decrease in heart rate (bradycardia). This contrasts with sympathetic activation, which raises heart rate by increasing cAMP and calcium currents.

More Multiple Choice Questions
Subscribe

Get the latest from Examzify

You can unsubscribe at any time. Read our privacy policy