钙通道阻滞剂和二价阳离子对去甲肾上腺素诱导的大鼠肛门尾骨肌收缩的影响。
Effect of calcium-entry blockers and divalent cations on noradrenaline-induced contractions of the rat anococcygeus muscle.
作者信息
Oriowo M A
出版信息
Arch Int Pharmacodyn Ther. 1984 Sep;271(1):45-52.
The effect of three calcium-entry blockers and two divalent cations known to inhibit Ca++ entry on noradrenaline (NA)--and potassium (K+)--induced contractions were studied. The organic calcium entry-blockers--diltiazem (2.5 X 10(-7)-2.5 X 10(-6) M), nifedipine (2.8 X 10(-7)-2.8 X 10(-6) M) and flunarizine (2.5 X 10(-7)-2.5 X 10(-6) M) did not significantly (P greater than 0.05) reduce NA (3.75 X 10(-7)-1.2 X 10(-5) M) contractions. However, these concentrations of the calcium entry-blockers significantly (P less than 0.05) reduced K+ (80 mM)-induced contractions of the anococcygeus muscle. Both NA- and K+-induced contractions of the anococcygeus muscle were concentration--dependently reduced by the divalent cations manganese (10(-4)-10(-3) M) and cobalt (10(-4)-10(-3) M). It is suggested that while NA-induced contractions are dependent on extracellular calcium, it is quite possible that the agonist NA and K+ activate different Ca++ channels or that the mechanism of activation of the Ca++ channels is different.
研究了三种钙通道阻滞剂以及已知可抑制钙离子内流的两种二价阳离子对去甲肾上腺素（NA）和钾离子（K+）诱导的收缩作用。有机钙通道阻滞剂——地尔硫䓬（2.5×10−7 - 2.5×10−6 M）、硝苯地平（2.8×10−7 - 2.8×10−6 M）和氟桂利嗪（2.5×10−7 - 2.5×10−6 M）并未显著（P＞0.05）降低NA（3.75×10−7 - 1.2×10−5 M）诱导的收缩。然而，这些浓度的钙通道阻滞剂显著（P＜0.05）降低了K+（80 mM）诱导的尾骨肌收缩。二价阳离子锰（10−4 - 10−3 M）和钴（10−4 - 10−3 M）浓度依赖性地降低了尾骨肌由NA和K+诱导的收缩。提示虽然NA诱导的收缩依赖于细胞外钙，但激动剂NA和K+很可能激活了不同的钙离子通道，或者钙离子通道的激活机制不同。
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