Regulatory mechanisms in endoluminal release of serotonin and substance P from feline jejunum.
The mechanisms controlling vagally induced 5-HT and SP release into the jejunal lumen were studied in the cat. In control animals, electrical vagal nerve stimulation doubled the rate of endoluminal secretion of 5-HT and SP. Propranolol pretreatment did not alter luminal secretion of these hormones. Atropine suppressed motor function and induced dose-related inhibition of vagal release of endoluminal 5-HT, but not of SP; the response to hexamethonium pretreatment was similar to that of atropine. In contrast, superior cervical ganglionectomy did not alter stimulated endoluminal 5-HT release but it completely abolished release into the portal vein. The portal 5-HT release was not affected by ganglionic blockade. The data suggest that vagally mediated 5-HT release into the lumen and the portal circulation are mediated by different neural mechanisms, the former cholinergic, the latter presumably adrenergic; and release of feline 5-HT and SP are independent, suggesting two intestinal sources, the EC cell for 5-HT and peptidergic neurons for SP.
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002415:Cats; D004558:Electric Stimulation; D005769:Gastrointestinal Motility / Q000187:drug effects; D018738:Hexamethonium; D006584:Hexamethonium Compounds / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D007583:Jejunum / Q000293:injuries / Q000378:metabolism*; D008297:Male; D011433:Propranolol / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000378:metabolism; D011950:Receptors, Cholinergic / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism*; D014630:Vagus Nerve / Q000502:physiology
D006584:Hexamethonium Compounds; D011941:Receptors, Adrenergic; D011950:Receptors, Cholinergic; D012701:Serotonin; D013373:Substance P; D018738:Hexamethonium; D001285:Atropine; D011433:Propranolol; D007545:Isoproterenol