New insights on relaxant effects of (—)‐borneol monoterpene in rat aortic rings

The monoterpene alcohol (?)‐borneol has many biological effects such as sedative, anti‐inflammatory, analgesic, anti‐nociceptive, antithrombotic and vasorelaxant effects. Our objective in this study was to investigate the mechanism of action of (?)‐borneol and determine its vasorelaxant effect. (?)‐Borneol was tested on isolated aortic rings contracted with PE (10^?6 m ). This study was performed in the absence or in the presence of endothelium, L‐NAME (100 μm ), indomethacin (10 μm ), TEA (1 and 10 mm ), 4‐AP (1 mm ) or glibenclamide (1 mm ) to assess the participation of EDRF, nitric oxide, prostanoids and potassium channels on the relaxing effect of (?)‐borneol. In this work, (?)‐borneol induced a relaxant effect in aortic rings, with and without endothelium, in a concentration‐dependent manner. The pharmacological characterization obtained using L‐NAME, indomethacin, TEA, 4‐AP and glibenclamide demonstrates that the effect of (?)‐borneol was modified in the presence of L‐NAME, indomethacin and glibenclamide showing that these signal transduction pathways are involved in the relaxing effect of the monoterpene. (?)‐Borneol has a vasorelaxant effect that depends on the presence of vascular endothelium, with the participation of nitric oxide and prostanoids. Also, (?)‐borneol displayed a direct action on the vascular smooth muscle, greatly dependent on K_ATP channels.