间尼索地平对大鼠主动脉收缩及^(45)Ca内流的影响(英文)

Effects of m-nisoldipine on contraction and ^(45)Ca influx in isolated rat aorta

间尼索地平浓度依赖性地抑制KCI引起的大鼠主动脉收缩IC_(50)=0.69(0.32—1.5)mmol·L^(-1)和^(45)Ca内流IC_(50)=0.35(0.06—2.0)nmol·L^(-1),对两者的抑制作用有良好的相关性(r=0.996),间尼索地平0.1—10μmol·L^(-1)不影响静息^(45)Ca内流,对NA所致的收缩和^(45)Ca内流亦无影响。间尼索地平舒张大鼠主动脉的作用主要是由于阻滞电压依赖性钙通道所致。

m-Nisoldipine caused a concentration-dependent depression of the contractile response and 45Ca influx evoked by KC1 in isolated rat thoracic aorta. The IC50 value for contraction and 45Ca influx were 0. 69 (95 % confidence limits 0. 32 - 1.5) nmol · L-1 and 0.35 (95 % confidence limits 0.06 - 2.0) nmol·L-1, respectively. There was a positive correlation between the inhibition of KC1-evoked contraction and 45 Ca influx (r = 0.996). m-Nisoldipine (0. 1 -10 μmol·L-1) did not influence the 45Ca influx into resting cells and failed to inhibit noradrenaline (1.0 μmol · L-1)-evoked contraction and 45Ca influx. The results suggest that the relaxant effect of m-nisodipine on rat aorta may be closely related to the blockade of Ca2+ entry through a potential-dependent calcium channel.