QuestionSBA
QuestionChoice
Histamine is secreted by enterochromaffin-like cells and binds H2 receptors. These receptors are Ga-s coupled GPCRs and stimulate adenylate cyclase, raising cAMP levels in parietal cells which, through activating the PKA phosphorylation of targets, leads to increased gastric acid secretion.
10001226
a
Histamine
QuestionChoice
Somatostatin is secreted by D-cells, binding Ga-i coupled somatostatin receptor GPCRs which inhibit adenylyl cyclase activity, reducing cAMP generation in parietal cells. This reduces PKA activation and by extension, its target phosphorylation which reduces gastric acid secretion.
10001229
d
Somatostatin
QuestionChoice
Gastrin is secreted by G-cells and binds CCK-B receptors and Ga-q coupled GPCRs which activate PLC. PLC generates IP3 which binds to IP3 receptors, causing calcium efflux from endoplasmic reticular stores in parietal cells which activates other effectors and leads to increased gastric acid secretion.
10001227
b
Gastrin
QuestionChoice
ACh is secreted by vagal efferents to the stomach and binds Ga-q coupled GPCR M3 muscarinic receptors which activate PLC. PLC generates IP3 which binds IP3 receptors, causing calcium efflux from endoplasmic reticular stores in parietal cells which activates other effectors and leads to increased gastric acid secretion.
10001228
c
Acetylcholine (ACh)
QuestionChoice
Ghrelin is secreted by cells of the gastric fundus when the stomach has been empty for several hours. It acts in the arcuate nucleus of the hypothalamus to stimulate neuropeptide-Y-secreting neurons which act on Y1/Y5 receptors of the lateral hypothalamus which signal hunger to other relevant parts of the brain involved in motivation, emotion and decision making such as the basal ganglia, amygdala and pre-frontal cortex. Ghrelin also stimulates AgRP-releasing neurons which antagonise a-melanocyte stimulating hormone at melanocortin 3/4 receptors in the ventromedial hypothalamus to reduce the generation of satiety signals.

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10001230
e
Ghrelin
Concept
Chapter
2693
3776
Gastric Secretion
Topic
149
Gastro-intestinal physiology
12792
Which factor secreted by enterochromaffin-like cells stimulates gastric acid secretion by parietal cells?
a