Calcitonin gene‐related peptide inhibits exocrine secretion from the rat pancreas by a neurally mediated mechanism

NW Bunnett, SJ Mulvihill, HT Debas

Research output: Contribution to journalArticlepeer-review

Abstract

The mechanism by which calcitonin gene‐related peptide (CGRP) inhibits exocrine secretion from the rat pancreas was examined in the isolated, vascularly perfused pancreas and in vitro using freshly isolated pancreatic acini. CGRP (10(‐10)‐10(‐7) M) inhibited the volume and protein output from the perfused pancreas, stimulated by a mixture of the cholecystokinin octapeptide CCK8 (10(‐10) M) and secretin (10(‐8) M). The inhibition by CGRP was dose related and maximal at 10(‐8) M (P less than 0.05). CGRP (10(‐8) M) failed to inhibit amylase secretion from isolated pancreatic acini, stimulated by graded concentrations of CCK8 (10(‐13)‐10(‐8) M). This implies an indirect mechanism of inhibition. The mechanism of inhibition was investigated in the isolated, vascularly perfused pancreas using tetrodotoxin, atropine and hexamethonium (all 10(‐7) M). Tetrodotoxin and atropine but not hexamethonium prevented the inhibition of volume and protein secretion by CGRP (10(‐8) M) (P less than 0.05). Tetrodotoxin, atropine and hexamethonium were without effect on exocrine secretion stimulated by CCK8 and secretin (controls). These results indicate that CGRP inhibits pancreatic exocrine secretion by an indirect, neurally mediated mechanism involving cholinergic‐muscarinic transmission.

Original languageEnglish (US)
Pages (from-to)115-123
Number of pages9
JournalExperimental Physiology
Volume76
Issue number1
DOIs
StatePublished - Jan 1 1991

ASJC Scopus subject areas

  • Physiology
  • Nutrition and Dietetics
  • Physiology (medical)

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