Vagal stimulation of duodenal HCO3(-)-secretion in anaesthetized rats.
The present study was designed to examine the influence of the vagal nerves on mucosa protective duodenal HCO3(-)-secretion in chloralosed rats. The HCO3(-)-secretion was measured by in situ titration in a duodenal segment devoid of Brunner glands. Cervical vagotomy lowered duodenal HCO3(-)-secretion and stimulation of the cut vagal nerves (10 Hz for 15 min) increased this secretion. Both basal and vagally stimulated duodenal HCO3(-)-secretions were more pronounced in rats with ligated adrenal glands. Atropine did not influence basal duodenal HCO3(-)-secretion, whereas indomethacin and hexamethonium lowered basal secretion in vagotomized rats with ligated adrenal glands. Compared with untreated controls, vagally induced secretory responses were unchanged by atropine, 50% smaller in indomethacin treated rats and almost abolished in rats treated with hexamethonium. The study suggests that the vagal nerves exert an excitatory effect on duodenal HCO3(-)-secretion which is mainly mediated via nicotinic, non-muscarinic transmission, in part dependent on prostaglandin synthesis. Furthermore, the results indicate that the adrenal glands exert an inhibitory action on both the basal and vagally induced mucosa protective HCO3(-)-secretion.
D000311:Adrenal Glands / Q000502:physiology; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects; D004386:Duodenum / Q000502:physiology*; D004558:Electric Stimulation; D006339:Heart Rate / Q000187:drug effects; D018738:Hexamethonium; D006584:Hexamethonium Compounds / Q000494:pharmacology; D006854:Hydrocortisone / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014630:Vagus Nerve / Q000502:physiology*
D001639:Bicarbonates; D006584:Hexamethonium Compounds; D018738:Hexamethonium; D006854:Hydrocortisone; D007213:Indomethacin