Different relaxation effect of cinnarizine and nimodipine on isolated arteries

Key words: 
• nimodipine /
• cinnarizine /
• vascular endothelium /
• relaxation

Abstract: Objective:This study was designed to investigate the different relaxation effect of cinnarizine and nimodipine on isolated arteries.Methods:Arteries were isolated from sixteen male Sprague-Dawley rats weighing 220～250 g,carefully dissected from sur- rounding fat and connective tissues,and cut into 2～3 mm-long circular segments.These segments were initially contracted with pheny- lephrine(1μM).When the contraction reached a steady state,cumulative concentration-respense(CR)curves to cinnarizine or ni- modipine were obtained by adding increasing concentrations to the segments that functional endothelium was present or absent.Re- sults:Both cinnarizine and nimodipine produced concentration-dependent relaxation on the segments that functional endothelium was present or absent.Nimodipine produced stronger relaxation on endothelium complete segments than on the endothelium removal ones. Cinnarizine produced a same relaxation on endothelium-complete segments and endothelium-removed ones.Conclusion:Cinnarizine and nimodipine produced different relaxation effects on endothelium-complete segments and endothelium-removed ones.The differ- ence between cinnarizine and nimodipine was depended on the integrity of the vascular endothelium.