The Effect of Papaverine on L-Type Ca2+ Current in Rat Basilar Smooth Muscle Cells

ABSTRACT

OBJECTIVE: Papaverine has been used to manage vasospasm after subarachnoid hemorrhage. However, its mechanism for cerebrovascular smooth muscle are still not clear. This study was undertaken to investigate the effect of papaverine on L-type Ca2+ channels directly by using patch clamp techniques in freshly isolated single smooth muscle cells from rat basilar artery. METHODS: Whole-cell patch clamp technique was used for measuring the amplitude of L-type Ca2+ current. Papaverine was added to the bath solution. RESULTS: Patch clamp studies revealed a whole-cell current which resembles the L-type Ca2+ current reported by others. The amplitude of this current was decreased by nimodipidine and increased by Bay K 8644. Papaverine 100 micro M reduced the amplitude of the L-type Ca2+ channel current. CONCLUSION: We can conclude that papaverine may relax cerebral vessel through decreasing level of intracellular calcium, [Ca2+]i, by inhibition of L-type Ca2+ channel.