title: Neurohormonal regulation of secretin secretion in canine duodenal mucosa in vitro.
abstract: We examined the effects of cholinergic, peptidergic and GABAergic agents on secretin secretion from canine duodenal mucosal explants incubated in organ culture media. Carbachol (10(-12) to 10(-4) M), atropine (10(-6) to 10(-4) M), hexamethonium (10(-6) to 10(-4) M), and somatostatin did not alter basal secretion of secretin. Somatostatin (10(-7) to 10(-8) M) inhibited secretin secretion stimulated by pH 4.5. Met, Leu and their D-ala2-analogs inhibited both basal and pH 4.5-stimulated secretin. Naloxone reversed the inhibition caused by met-enkephalin at pH 7.4. GABA (10(-9) to 10(-6) M) stimulated both basal and pH 4.5-stimulated secretin secretion. GABA-stimulated secretin secretion was neuronal in nature, bicuculline sensitive and was mediated via post ganglionic cholinergic neurons. GABA-stimulated secretin secretion was inhibited by both somatostatin and metenkephalin, suggesting that GABA-stimulated secretin secretion may be under the inhibitory control of peptidergic agents as well.
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001640:Bicuculline / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D004285:Dogs; D004386:Duodenum / Q000187:drug effects / Q000378:metabolism*; D018738:Hexamethonium; D006584:Hexamethonium Compounds / Q000494:pharmacology; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000502:physiology*; D012633:Secretin / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
chemical_list: D006584:Hexamethonium Compounds; D018377:Neurotransmitter Agents; D012633:Secretin; D018738:Hexamethonium; D005680:gamma-Aminobutyric Acid; D001285:Atropine; D002217:Carbachol; D001640:Bicuculline