Terpinen-4-ol: Mechanisms of relaxation on rabbit duodenum

Nascimento N.R.F.; Leal-Cardoso J.H.; Lessa L.M.A.; Roriz-Filho J.S.; Cunha K.M.A.; Fonteles M.C.

Terpinen-4-ol: Mechanisms of relaxation on rabbit duodenum

Tipo

Artigo

Data de publicação

2005

Periódico

Journal of Pharmacy and Pharmacology

Citações (Scopus)

14

Autores

Nascimento N.R.F.
Leal-Cardoso J.H.
Lessa L.M.A.
Roriz-Filho J.S.
Cunha K.M.A.
Fonteles M.C.

Resumo

The effect of terpinen-4-ol was studied on rabbit duodenum in-vitro. Terpinen-4-ol induced relaxation of the basal tonus (IC50 170.2 (95% confidence interval, 175-204) μM) with a maximal relaxant response of 180.4 ± 3.9% (n = 6) of the contraction induced by 60 mM [K+]. The maximal relaxation induced in control conditions was not affected (P>0.05) by pretreatment of the tissues with phentolamine (50 μM) or propranolol (10 μM), NG nitro-L-arginine methyl ester (L-NAME; 1 mM), 1H-(1,2,4)-oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 100 μM), hexamethonium (1 μM), tetrodotoxin (1 μM), the mixture charybdotoxin-apamin (1 μM), glibenclamide (10 μM), 4-aminopyridine (10 μM) or tetraethyl-ammonium (100 μM). In addition, terpinen-4-ol completely relaxed tissues precontracted with 60 mM [K+] solutions (IC50 325.9 (245.1-433.1) μM) and also blocked (IC50 154.7 (117.7-191.7) μM) the phasic component of this contraction. At a concentration of 195 and 650 μM it reduced by 41.3 ± 3.4% and 75.4 ± 3.1%, respectively the maximal contractile response to Ca2+ in depolarized duodenum. Terpinen-4-ol completely blocked the component of carbachol-induced contraction, which was resistent to nifedipine (100 μM) pretreatment or to a Ca2+-free solution. These data show that terpinen-4-ol relaxes intestinal smooth muscle and suggest that this effect is myogenic in nature and depends on calcium antagonism. © 2005 The Authors.