the-aps.org>meetings>eb

Natriuretic Peptides in the Gastrointestinal System
Sponsored by APS Gastrointestinal and Liver Physiology Section
Ion Channels and Transporters Tracks

The natriuretic peptides, which include atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP) and C-type natriuretic peptide (CNP), act as important modulators of blood volume and blood pressure and in addition can act as paracrine regulators of cellular function. Recent evidence suggests a significant role for these peptides in gastrointestinal physiology. ANP mRNA is expressed in both the stomach and intestine with substantial expression in the antrum of the stomach and ANP has been shown to be secreted from the stomach in response to cholinergic stimuli. ANP appears to be synthesized by enterochromaffin cells in rat gastric mucosa, particularly in the fundus of the stomach. Thus, ANP may act not only as a regional autocrine and paracrine regulator, but also as an endocrine regulatory peptide. Both the A-type and C-type natriuretic peptide receptors are present in the stomach and intestine and ANP, BNP  and CNP  have been shown to decrease gastric motility. Also, BNP decreases gastric emptying and gastrointestinal absorption. ANP appears to have a dual role in modulating acid secretion by the stomach. Centrally applied CNP enhances pancreatic secretion through a vagal pathway which suggests that the CNP response is mediated by the activation of natriuretic peptide guanylyl cyclase coupled receptors in the brain. Furthermore, CNP interacts with cholecystokinin and secretin in the brain to modify pancreatic secretion. This symposium will review the growing body of evidence supporting a role for natriuretic peptides in the regulation of gastrointestinal function.