Which of the following stimulate adenylate cyclase with G-protein coupled action ?
**Core Concept**
Adenylate cyclase is an enzyme responsible for converting ATP into cyclic AMP (cAMP), a secondary messenger involved in various cellular signaling pathways. The stimulation of adenylate cyclase is triggered by G-protein coupled receptors (GPCRs), which activate the Gs alpha subunit to stimulate adenylate cyclase activity.
**Why the Correct Answer is Right**
The correct answer stimulates adenylate cyclase through a G-protein coupled mechanism. This involves the binding of a ligand to a GPCR, which activates the Gs alpha subunit. The activated Gs alpha subunit then binds to and stimulates adenylate cyclase, leading to an increase in cAMP production. This signaling pathway is crucial in various physiological processes, including hormone secretion, smooth muscle relaxation, and increased heart rate.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a type of receptor that inhibits adenylate cyclase activity through a G-protein coupled mechanism, not stimulates it.
**Option B:** This option is incorrect because it is a type of enzyme that breaks down cAMP, not stimulates adenylate cyclase.
**Option C:** This option is incorrect because it is a type of receptor that stimulates phospholipase C, not adenylate cyclase.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that GPCRs can activate multiple signaling pathways, including the stimulation of adenylate cyclase, inhibition of adenylate cyclase, and activation of phospholipase C. Understanding the specific GPCR and its associated signaling pathway is crucial in understanding the physiological response to a particular ligand.
**Correct Answer:** C. Epinephrine stimulates adenylate cyclase with G-protein coupled action.