Enkephalinergic control of somatostatin secretion from the perfused rat stomach.
A role for the enkephalins in the regulation of gastric somatostatin (SLI) secretion has been investigated in an isolated perfused rat stomach model. Both methionine- and leucine-enkephalins caused a dose-dependent inhibition of gastric inhibitory polypeptide (GIP) stimulated SLI secretion. Leu-enkephalin was one order of magnitude less potent than met-enkephalin: 50% inhibition by met-enkephalin was at 4 X 10(-9) M and with leu-enkephalin 3.5 X 10(-8) M. Naloxone (100 nM) had no effect on basal secretion but blocked the inhibitory action of met-enkephalin (1 nM or 1 microM). Vagal stimulation (7 V, 10 Hz, 5 ms) inhibited GIP-stimulated SLI release. Administration of naloxone partially reversed this inhibition, suggesting that endogenous opioids were at least partially responsible for vagally induced inhibition. A number of possible pathways by which endogenous enkephalins may modulate SLI release have been proposed.
D000818:Animals; D004745:Enkephalins / Q000494:pharmacology / Q000502:physiology*; D005749:Gastric Inhibitory Polypeptide / Q000494:pharmacology; D005753:Gastric Mucosa / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000378:metabolism*; D013270:Stomach / Q000294:innervation; D014630:Vagus Nerve / Q000502:physiology
D004745:Enkephalins; D009270:Naloxone; D013004:Somatostatin; D005749:Gastric Inhibitory Polypeptide