Investigation of Mechanisms Involved in (−)-Borneol-Induced Vasorelaxant Response on Rat Thoracic Aorta

• Published in: Basic & clinical pharmacology & toxicology 2012-02, Vol.110 (2), p.171-177
• Main Authors: Silva-Filho, José Couras, Oliveira, Nelma Neylanne P. M., Arcanjo, Daniel D. R., Quintans-Júnior, Lucindo J., Cavalcanti, Sócrates C. H., Santos, Márcio Roberto V., Oliveira, Rita de Cássia M., Oliveira, Aldeídia P.
• Format: Article
• Language: English
• Subjects: 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester - adverse effects; 4-Aminopyridine - pharmacology; Animals; Aorta; Aorta, Thoracic - drug effects; Arteries; Biological and medical sciences; Bornanes - pharmacology; Caffeine; Calcium channels; Calcium Chloride - adverse effects; Calcium influx; Calcium mobilization; Depolarization; Endothelium; Endothelium, Vascular - drug effects; Endothelium, Vascular - metabolism; Essential oils; glibenclamide; Glyburide - pharmacology; Medical sciences; Medicinal plants; Monoterpenes; Pharmacology. Drug treatments; phenylephrine; Phenylephrine - adverse effects; Potassium channels; Potassium Channels - drug effects; Potassium Chloride - adverse effects; Rats; Tetraethylammonium; Tetraethylammonium - pharmacology; Thorax; Vasodilation; Vasodilator Agents - pharmacology
• ISSN: 1742-7835; 1742-7843
• DOI: 10.1111/j.1742-7843.2011.00784.x

:  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.