The different suppression on voltage-dependent potassium channels currents of smooth muscle cells from cerebral pial arteries and penetrating arteries by subarachnoid hemorrhage / 中华神经科杂志

ABSTRACT

Objective To study the effect of subarachnoid hemorrhage (SAH) on voltagedependent potassium channels (Kv) currents of smooth muscle cells,which is hypothesized to be different between cerebral pial arteries and penetrating arteries.Methods Smooth muscle cells from cerebral pial arteries and penetrating arteries in rats were enzymatically isolated 72 h after SAH,and patch clamp was used to test the relative cell size,resting potential and Kv currents.Results Resting potential of either pial ((45.63 ±1.18) mV) or penetrating artery ((41.55-± 1.19) mV) was shifted positively by SAH,even more significantly in latter (F =8.24,P ＜ 0.05 ; F =9.36,P ＜ 0.01) ; Resting potential of pial artery of control ((38.76 ± 1.03) mV),penetrating artery of control ((38.53 ± 0.67) mV),pial artery of SAH ((36.87 ± 1.49) mV) and penetrating artery of SAH((37.89 ± 1.24) mV) were shifted positively to the same level by 1 μmol/L 4-aminopyridine (4AP; F =3.08,P ＞0.05).Maximum Current Density (Imax) of either pial ((20.82 ±0.59) pA/pF) or penetrating artery ((15.15 ±0.37) pA/pF) was compromised by SAH,also more significantly in latter (F =6.22,P ＜ 0.05) ; Imax of pial artery of control (9.15 ± 0.16),penetrating artery of control (9.04 ± 0.36),pial artery of SAH (8.77 ± 0.26) and penetrating artery of SAH (9.12 ± 0.17) were decreased to the same level by 1 μmol/L 4AP (F =2.96,P ＞ 0.05).Conclusions SAH probably shares the similar pathway with Kv blocker (4AP) in Kv currents inhibition.Further,SAH differently inhibits smooth muscle cells Kv currents and resting potential of cerebral pial arteries and penetrating arteries,which may be related with their different sensitivity towards cerebral vasospasm following SAH.