Kimura I, Kimura M, Yoshimura Y
Arch Int Pharmacodyn Ther. 1981 Jul;252(1):40-52.
The suppression of the Ca spike frequency generated spontaneously in the guinea-pig taenia coli was quantitatively investigated using the single sucrose gap method in an attempt to correlate frequency with the relaxation induced by Ca antagonists, isoproterenol and papaverine. The intrinsic activity (a) of depleted Ca that gave the maximal response in the dose-spike frequency curve (DSfC) or dose-tension curve (DTC) was taken as unity. Verapamil and MnCl2: a of both the DSfC and DTC were 1.0. Papaverine: a of the DSfC was 0.5 in contrast to 1.0 in the case of the DTC, and the affinity of the DSfC was somewhat less than that of the DTC. Isoproterenol: a and affinity of the DSfC were considerably less than in the case of the DTC. These results indicate that (1) relaxation induced by the Ca antagonists we used clearly corresponded to the suppression of the Ca influx carrying the action potential, (2) the relaxation induced by isoproterenol was not due to direct suppression of Ca influx, and (3) papaverine and depleted Ca influenced Ca both directly and indirectly.U
采用单蔗糖间隙法对豚鼠结肠带自发产生的Ca尖峰频率抑制进行了定量研究，试图将频率与钙拮抗剂、异丙肾上腺素和罂粟碱诱导的舒张相关联。在剂量-尖峰频率曲线（DSfC）或剂量-张力曲线（DTC）中产生最大反应的耗尽Ca的内在活性（a）被视为1。维拉帕米和MnCl2：DSfC和DTC的a均为1.0。罂粟碱：DSfC的a为0.5，而DTC的a为1.0，且DSfC的亲和力略低于DTC。异丙肾上腺素：DSfC的a和亲和力远低于DTC。这些结果表明：（1）我们使用的钙拮抗剂诱导的舒张明显对应于携带动作电位的Ca内流的抑制；（2）异丙肾上腺素诱导的舒张不是由于直接抑制Ca内流；（3）罂粟碱和耗尽的Ca对Ca有直接和间接影响。
