부산대학교 도서관

The monoterpene (−)-borneol is present in essential oils of several medicinal plants. The aim of this study was to evaluate (−)-borneol effects on rat thoracic aorta artery rings. The cumulative addition of (−)-borneol (10−9-3 × 10−4 M) on a phenylephrine-induced pre-contraction (10−6 M) promoted a vasorelaxant effect in a concentration-dependent manner and independent of vascular endothelium. A similar effect was obtained on KCl-induced pre-contractions (80 mM). (−)-Borneol (10−5-3 × 10−4 M) inhibited contractions induced by cumulative addition of CaCl2 (10−6-3 × 10−2 M) in depolarizing medium without Ca2+ in a concentration-dependent manner. On S-(−) Bay K 8644-induced pre-contractions (10−7 M), (−)-borneol did not induce significant changes compared with KCl-induced pre-contractions. In a Ca2+-free medium, (−)-borneol (10−5, 10−4 or 10−3 M) interfered in calcium mobilization from phenylephrine (10−6 M)- or caffeine (20 mM)-sensitive intracellular stores. The involvement of K+ channels was evaluated by tetraethylammonium (3 mM), 4-aminopyridine (1 mM) and glibenclamide (10−5 M) pre-treatment, and (−)-borneol-induced vasorelaxation was markedly attenuated. Thus, this vasorelaxant effect can probably be attributed to calcium influx blockade through voltage-operated calcium channels (CaVL), calcium mobilization from intracellular stores and potassium channels activation. [ABSTRACT FROM AUTHOR]