Iranian Journal of Pharmaceutical Research (2004): Supplement 2:
2nd International Congress on Traditional Medicine and Materia Medica
Relaxatory effect of Vitis vinifera leaf extract on rat isolated trachea
Gharib Naseri M.K., Heidari A.
Department of Physiology, Medical School, Ahwaz University of Medical Sciences, Ahwaz, Iran
In previous studies, we have shown the relaxatory effect of grape leaf (Vitis vinifera) extract on isolated ileum, uterus and aorta. In rat aorta it was revealed that the NO and endothelium are involved in the relaxation induced by grape leaf extract. The aim of present study was to investigate the effect of the Vitis vinifera leaf hydroalcoholic extract (VLHE) on rat trachea precontracted by Ach and KCl.
Extract was prepared by maceration method using 70% alcohol for 72 hours and then, the solvent was evaporated. Male Sprague Dawley rats were anaesthetized by ketamine hydrochloride (50 mg/kg i.p.), the trachea (5-6 cartilage rings) were isolated and suspended in an organ bath containing Kreb’s solution (37ºC, pH 7.4) bubbled with oxygen. Following 60 min period equilibrium, tissue was contracted by either Ach (55 µM) or KCl (60 mM) under 1.5 g initial tension and tissue responses were recorded isometrically. After reaching to plateau, different concentrations of VLHE (0.5, 1, 2, 4 and 8 mg/ml) applied to the organ bath in a non-cumulative manner. Results are presented in mean±SEM of g contraction force.
Trachea precontracted by Ach or KCl were relaxed by VLHE significantly (P<0.0001). The relaxatory effect of VLHE was dose dependent and reversible since the contractility of the trachea was returned to normal after removing the extract from media. Applying neither NO synthase inhibitor (L-NAME 100 µM) nor ß-adrenergic receptor antagonist (propranolol 1 µM) to the organ bath prior to evoked contractions by Ach and KCl did not modify the tracheal relaxation induced by extract (3 mg/ml).
It seems that the Vitis vinifera leaf hydroalcoholic extract reduced trachea contraction through blockade of voltage dependent calcium channels and also NOergic and adrenergic system are not involved in this inhibitory effect of VLHE.