豚鼠气管平滑肌细胞钾离子通道动力学特性及对拮抗剂的敏感性  

Kinetic properties and sensitivity to antagonists of K + channels in guinea pig tracheal smooth muscle 1

作　　者：蔡绍曦[1] 邹飞[1] 佟振清 刘久山[1] 

机构地区：[1]第一军医大学第一附属医院呼吸内科

出　　处：《中国药理学与毒理学杂志》1997年第3期206-210,共5页Chinese Journal of Pharmacology and Toxicology

基　　金：国家自然科学基金

摘　　要：钾离子通道功能与细胞的兴奋性有关，在豚鼠支气管平滑肌细胞膜上，用膜片钳技术证实了一类电压依赖性钾通道的存在，该通道电导为７５±５ｐＳ，翻转电位为－７３±８ｍＶ．动力学特性显示，通道开放时程分布直方图符合双指数拟合．其中τ０２随去极化程度增大而增大．通道开放概率有明显的电压依赖性．该类通道可被四乙胺从膜的内，外侧面阻断，对４－氨基吡啶不敏感．可被铯离子阻断，通道活动与细胞内钙水平降低无关．提示钾离子通道特性在不同组织细胞上有差异．To determine the characteristics of potassium(K +) channels, which are suggested to be associated with recovery of excitable cells after depolarization, the elementary currents flowing through single channels opened by depolarization were studied from acutely dissociated airway smooth muscle of guinea pig using patch clamp technique. The single channel conductance determined from the slop of the current voltage curve is 75±5 pS, and the reversal potential is -73±8 mV. The kinetic analysis of K + channels showed that currents generate a biexponential distribution of open time in all patches. Within a certain voltage range, the longer time constant increases with depolarization. The open probability is also strongly dependent on membrane potential. The channel activities are blocked by tetraethylammonium applied intracellular or extracellular, but which is insensitive to 4 aminopyridine. Outward currents can be completely blocked by Cs + replaced K +. Nevertheless, It is independent of intracellular Ca 2+ levels. The results suggest that heterogeneity of K + channels exists in different tissues.

关 键 词：钾离子通道 膜片钳制 气管平滑肌 拮抗剂 

分 类 号：R337.5[医药卫生—人体生理学]