title: Involvement of different receptors in the central and peripheral effects of histamine on intestinal motility in the rat.
abstract: The effects of histamine on intestinal motility have been investigated in conscious rats, fed or fasted, using an electromyographic method. Histamine peripherally administered (10 mg kg-1) in 15 h fasted rats induced an inhibition followed by a period of irregular spiking activity disrupting the duodenojejunal migrating myoelectric complexes (MMC) and suppressed the postprandial motor spiking activity when administered 50 min after a meal. The selective agonist of the H1-receptors, 2-pyridylethylamine (2-PEA) induced an irregular spiking activity while dimaprit acting on H2-receptors, inhibited the MMC pattern. Effects of peripherally administered histamine were antagonized by previous administration of chlorpheniramine (0.5 mg kg-1 i.p.) and in a lesser extent by cimetidine (10 mg kg-1 i.p.). Histamine (1-10 micrograms) administered intracerebroventricularly (i.c.v.) in fasted rats increased the motor cycle frequency and immediately restored the MMC pattern when given to fed rats. Among the three agonists of the H1- H2- and H3-receptors (2-PEA, dimaprit and R-alpha-methylhistamine, respectively) only R-alpha-methylhistamine (1-10 micrograms i.c.v.) was able to reproduce this effect. It is concluded that the effects of histamine on intestinal motility were centrally and peripherally mediated involving mainly H1-receptors at the peripheral level and H3-receptors at the CNS level.
authors.affiliation: Department of Pharmacology, INRA, Toulouse, France.
authors.forename: M J
authors.initials: MJ
authors.lastname: Fargeas
authors.forename: J
authors.initials: J
authors.lastname: Fioramonti
authors.forename: L
authors.initials: L
authors.lastname: Bueno
mesh_terms: D000818:Animals; D002744:Chlorpheniramine / Q000494:pharmacology; D017259:Dimaprit; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006632:Histamine / Q000008:administration & dosage / Q000494:pharmacology*; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D008297:Male; D008761:Methylhistamines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011968:Receptors, Histamine / Q000502:physiology*; D013890:Thiourea / Q000494:pharmacology
chemical_list: D006634:Histamine H1 Antagonists; D006635:Histamine H2 Antagonists; D008761:Methylhistamines; D011968:Receptors, Histamine; D002744:Chlorpheniramine; D006632:Histamine; D013890:Thiourea; C048140:N-methylhistamine; D017259:Dimaprit