title: Evidence for serotonergic system involvement in the effect of morphine on gastrointestinal motility in the rat.
abstract: 1. Intestinal motility was measured by the transit of charcoal meal through the small intestine of the rat. 2. Morphine given subcutaneously induced a reduction in the gastrointestinal transit (GIT), and the response was dose-dependent (0.1-2.5 mg/kg). 3. The inhibitory effect of morphine was antagonized by prior subcutaneous administration of naloxone (1 mg/kg). 4. Depletion of serotonergic neurons by para-chlorophenylalanine (100 mg/kg, ip, 3 days) completely abolished the inhibitory action of morphine. 5. Methysergide (5 mg/kg, sc) and ketanserin (5 mg/kg, sc) also reduced the morphine effect. 6. Destruction of serotonergic neurones by intracerebroventricular injection of 5,7-dihydroxytryptamine (20 mu/kg) abolished the effect of morphine. 7. These observations provide some evidence for the involvement of a central serotonergic system in the effect of morphine on gastrointestinal motility.
authors.affiliation: Department of Pharmacology, Faculty of Medicine, Medical Sciences University of Shahid-Beheshti, Evin, Tehran, Iran.
authors.forename: M H
authors.initials: MH
authors.lastname: Pourgholami
authors.forename: F
authors.initials: F
authors.lastname: Goshadrou
mesh_terms: D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology; D000818:Animals; D002490:Central Nervous System / Q000187:drug effects; D002606:Charcoal; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D010134:Fenclonine / Q000494:pharmacology; D005277:Fenfluramine / Q000494:pharmacology; D005769:Gastrointestinal Motility / Q000187:drug effects*; D007650:Ketanserin / Q000494:pharmacology; D008297:Male; D009020:Morphine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D012701:Serotonin / Q000502:physiology*
chemical_list: D002606:Charcoal; D005277:Fenfluramine; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D009270:Naloxone; D009020:Morphine; D007650:Ketanserin; D010134:Fenclonine