Gastrointestinal Physiology · NEET PG Preparation Physiology
Acid secretion by gastric parietal cells is stimulated by acetylcholine, histamine, and gastrin. Which of the following intracellular second messenge…
Practice question from Gastrointestinal Physiology (NEET PG Preparation Physiology), with the correct answer and a step-by-step solution.
medium · MCQ · Q-AC101C
Acid secretion by gastric parietal cells is stimulated by acetylcholine, histamine, and gastrin. Which of the following intracellular second messenger systems is primarily activated by histamine binding to its H2 receptor on the parietal cell?
- A.Phospholipase C / IP3 / Ca2+
- B.Adenylyl cyclase / cAMPCorrect answer
- C.Receptor tyrosine kinase
- D.cGMP pathway
Solution
Histamine binds to H2 receptors, which are Gs-protein coupled receptors that activate adenylyl cyclase, increasing intracellular cAMP levels and subsequently activating protein kinase A (PKA). Gastrin and acetylcholine act primarily via the phospholipase C / IP3 / intracellular calcium pathway.
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