Planta Med 2016; 82(15): 1329-1334
DOI: 10.1055/s-0042-104657
Biological and Pharmacological Activity
Original Papers
Georg Thieme Verlag KG Stuttgart · New York

α-Terpineol Induces Gastric Retention of Liquids by Inhibiting Vagal Parasympathetic Pathways in Rats

Moisés Tolentino Bento da Silva
1   Department of Physical Education, Federal University of Piaui, Teresina, PI, Brazil
2   Center for Research on Medicinal Plants, Federal University of Piaui, Teresina, PI, Brazil
,
Rosemarie Brandim Marques
2   Center for Research on Medicinal Plants, Federal University of Piaui, Teresina, PI, Brazil
,
Francisco José Batista-Lima
3   Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil
,
Marília Almeida Soares
3   Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil
,
Armênio Aguiar dos Santos
3   Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil
,
Pedro Jorge Caldas Magalhães
3   Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil
,
Francisco de Assis Oliveira
2   Center for Research on Medicinal Plants, Federal University of Piaui, Teresina, PI, Brazil
,
Fernanda Regina de Castro Almeida
2   Center for Research on Medicinal Plants, Federal University of Piaui, Teresina, PI, Brazil
› Author Affiliations
Further Information

Publication History

received 03 November 2015
revised 11 February 2016

accepted 02 March 2016

Publication Date:
28 April 2016 (online)

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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 by α-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 by α-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 by α-terpineol appears not to result from a direct action of the monoterpene on gastric smooth muscle cells.