Vasorelaxant effect of Rho kinase inhibitor DL0805-0 on isolated rat aortic rings and its underlying mechanisms / 中国药理学通报

ABSTRACT

Aim To investigate the in vitro vasorelax-ant effect of DL0805-0, a Rho kinase inhibitor, on iso-lated rat thoracic aorta and explore its underlying mechanism. Methods Tension was measured to eval-uate the vasorelaxant effect of DL0805-0 on rat endo-thelium-intact and endothelium-denuded thoracic aorta rings. Rho kinase inhibitor fasudil, nitric oxide syn-thase inhibitor Nω-nitro-L-arginine methyl ester ( L-NAME), guanylate cyclase inhibitor methylene blue, cyclooxygenase inhibitor indomethacin, calcium-activa-ted potassium channel blocker tetraethyl ammonium ( TEA ) , ATP-sensitive potassium channel blocker glibenclamide and voltage-dependent potassium chan-nel blocker 4-aminopyridine ( 4-AP ) were used to il-lustrate the mechanisms of vasorelaxant effect of DL0805-0 . Results DL0805-0 exerted vasorelaxation in a dose-dependent manner in KCl (60 mmol·L-1 ) or NE ( 0. 1 μmol · L-1 ) -induced contraction. DL0805-0-induced vasorelaxation was significantly re-duced by L-NAME. However, methylene blue and in-domethacin did not significantly affect vasorelaxation of DL0805-0. In endothelium-denuded rings, TEA re-markably attenuated the vasorelaxant effect of DL0805-0 , while glibenclamide and 4-AP did not affect vasore laxation of DL0805-0 significantly. DL0805-0 also re-duced NE-induced transient contraction and inhibited contraction induced by increasing extracellular calci-um. Conclusion These results suggest that DL0805-0 induces vasorelaxation through an endothelium-depend-ent pathway. The opening of calcium-activated K+channels and blocking of Ca2+ channels in vascular smooth muscle cells may be one of the mechanisms of DL0805-0-induced vasorelaxation.