title: α-Terpineol Induces Gastric Retention of Liquids by Inhibiting Vagal Parasympathetic Pathways in Rats.
abstract: α-Terpineol is a monoterpene with smooth muscle relaxant properties. In this study, its effects on the gastric emptying rate of awake rats were evaluated with emphasis on the mode by which it induces gastrointestinal actions. Administered by gavage,α-terpineol (50 mg/kg) delayed gastric emptying of a liquid test meal at 10 min postprandial. Hexamethonium or guanethidine did not interfere with the retarding effect induced byα-terpineol, but atropine and L-NG-nitroarginine methyl ester abolished it. In vagotomized rats,α-terpineol did not delay gastric emptying. In isolated strips of gastric fundus, concentration-effect curves in response to carbamylcholine were higher in magnitude after treatment with the monoterpene.α-Terpineol (1 to 2000 µM) relaxed sustained contractions induced by carbamylcholine or a high K+concentration in a concentration-dependent manner. This relaxing effect was not affected by the presence of L-NG-nitroarginine methyl ester, 1 H-[1, 2, 4]oxadiazolo[4,3-a]quinoxalin-1-one, tetraethylammonium, or atropine. Smooth muscle contractions induced by electrical field stimulation were inhibited byα-terpineol. In conclusion,α-terpineol induced gastric retention in awake rats through mechanisms that depended on intact vagal innervation to the stomach, which involved cholinergic/nitrergic signalling. Such a retarding effect induced byα-terpineol appears not to result from a direct action of the monoterpene on gastric smooth muscle cells.
authors.affiliation: Department of Physical Education, Federal University of Piaui, Teresina, PI, Brazil.
authors.forename: Moisés Tolentino Bento
authors.initials: MT
authors.lastname: da Silva
authors.affiliation: Center for Research on Medicinal Plants, Federal University of Piaui, Teresina, PI, Brazil.
authors.forename: Rosemarie Brandim
authors.initials: RB
authors.lastname: Marques
authors.affiliation: Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil.
authors.forename: Francisco José
authors.initials: FJ
authors.lastname: Batista-Lima
authors.affiliation: Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil.
authors.forename: Marília Almeida
authors.initials: MA
authors.lastname: Soares
authors.affiliation: Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil.
authors.forename: Armênio Aguiar
authors.initials: AA
authors.lastname: Dos Santos
authors.affiliation: Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil.
authors.forename: Pedro Jorge Caldas
authors.initials: PJ
authors.lastname: Magalhães
authors.affiliation: Center for Research on Medicinal Plants, Federal University of Piaui, Teresina, PI, Brazil.
authors.forename: Francisco
authors.initials: F
authors.lastname: de Assis Oliveira
authors.affiliation: Center for Research on Medicinal Plants, Federal University of Piaui, Teresina, PI, Brazil.
authors.forename: Fernanda Regina
authors.initials: FR
authors.lastname: de Castro Almeida
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D000081005:Cyclohexane Monoterpenes; D053138:Cyclohexenes / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005746:Gastric Emptying / Q000187:drug effects* / Q000502:physiology; D005748:Gastric Fundus / Q000187:drug effects*; D006145:Guanethidine / Q000494:pharmacology; D008297:Male; D039821:Monoterpenes / Q000008:administration & dosage / Q000494:pharmacology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D009924:Organ Culture Techniques; D011188:Potassium / Q000494:pharmacology; D017208:Rats, Wistar; D013565:Sympatholytics / Q000494:pharmacology; D014628:Vagotomy; D014630:Vagus Nerve / Q000187:drug effects* / Q000378:metabolism / Q000601:surgery
chemical_list: D000081005:Cyclohexane Monoterpenes; D053138:Cyclohexenes; D039821:Monoterpenes; D013565:Sympatholytics; C016775:alpha-terpineol; D009569:Nitric Oxide; D001285:Atropine; D002217:Carbachol; D011188:Potassium; D019331:NG-Nitroarginine Methyl Ester; D006145:Guanethidine