小鼠精母细胞钙通道特性及硝苯地平的作用

Properties of calcium channels in mouse spermatocytes and effects of nifedipine

目的 为了建立一个合理、客观评价药物或毒物对生殖系统影响的细胞模型 ,研究了机械分离、未经酶消化的小鼠精母细胞Ca2 + 通道特性及硝苯地平对其的作用。方法 采用全细胞膜片钳技术。结果阻断K+ 电流后 ,当钳制电位 -90mV、指令电压 -80～ +1 0mV、步阶电压 1 0mV时 ,记录到Ca2 +电流 ,二价无机阳离子对Ca2 + 电流的抑制作用Ni2 +>Cd2 + ,而L型Ca2 + 通道激动剂BayK8644对电流无任何影响。分析小鼠精母细胞上记录的Ca2 + 电流为T型Ca2 + 通道开放产生。L型Ca2 + 通道阻断剂硝苯地平对精母细胞Ca2 + 电流有明显的抑制作用 ,半数最大抑制浓度为 0 .3 9μmol·L-1,而且细胞外液冲洗恢复缓慢 ,这支持了二氢吡啶类药物可用于男性避孕。结论 机械分离。

AIM For establishing a reasonable and objective cell model to evaluate the effect of drug or toxicant on reproductive system, the pro perties of Ca 2+ channel of mouse spermatogenic cells, isolated by a mechanical method devoid of enzymalic digestion, were observed. METHODS Using whole cell patch clamp technique. RESULTS Ca 2+ currents were obtained by stepping membrane potential to voltage between -80 and +10 mV, in 10 mV increments from a holding potential of -90 mV. Accordingly, the inhibitory percentage of NiCl 2 on Ca 2+ current was more than that of CdCl 2. Furthermore, Bay K8644, an agonist of L type Ca 2+ channel, had little effects on these Ca 2+ currents. So Ca 2+ channels presented in mouse spermatogenic cells belong to T type channels. Unexpectedly, nifedipine significantly inhibited peak currents as low as micromolar concentration, and currents recoverd slowly after the removal of nifedipine, which conforms with it′s contraceptive intervention in human males. CONCLUSION The model can be used in pharmacological and toxicological study.