Abstract: Objective To study the effect of ISL on the cerebral basilar artery in Wistar rat. Methods After perfusion with 10-5 mol/L PE、10-5 mol/L PE+10-4 mol/L ISL and 10-5 mol/L PE, pressure myograph was used to measure the diameter of the cerebral basilar artery in rat ; The whole cell patch clamp recording technique was used to investigate the effects of 10-7、10-6、10-5、10-4 and 3×10-4mol/L ISL on the membrane current of VSMC in rat cerebral basilar artery. Results 1) 10-4 mol/L ISL relaxed the cerebral basilar artery(p<0.05). 2) ISL enhanced the membrane current of VSMC in both voltage-dependent and concentration-dependent manners(p<0.05). EC50 of ISL enhanced the VSMC outward current was 9.5μmol/L. In the presence of 10-3 mol/L TEA for 3 min, the enhanced current induced by ISL in VSMCs was ablished, and the current reduced to (86±22) pA, 0.65 ± 0. 04 times compared with the control group( p＜0.05). Conclusion ISL relaxed the cerebral basilar atery via the enhancement of the outward current mediated by BKCa channel in Wistar rat.

Key words: cerebral basilar atery, ISL, BKCa channel, patch clamp