NO-cGMP通路对下丘脑钙激活钾通道的调控研究

目的研究一氧化氮（ＮＯ）对ＳＤ乳鼠下丘脑神经元钙激活钾（ＫＣａ）通道的作用及其机制。方法采用内面向外 式及细胞贴附式膜片钳技术比较浴槽液中加入１００μmol/L硝普钠（ＳＮＰ）前后动物下丘及神经元ＫＣａ通道动力学 的改变。结果细胞贴附式时浴槽液中加入１００μmol/L ＳＮＰ，通道开放概率由（７．３±１．５）％升高至（４０．２±６．５）％，开放时 间由（７．１２±１．４１） ｍｓ增大至（１５．３４±３．４５） ｍｓ，开放频率由（１１．３±３．５）Ｈz升高为（２６．６±４．２） Ｈz（ｎ＝１０， Ｐ＜０．０５）。结论 ＮＯ－cＧＭＰ通路可显著提高通道的开放概率，这种增强作用是通过延长通道开放时间及增加开放频率实现的，它的 病理或生理作用还有待于进一步研究。

Study of calcium-activated potassium channels regulation in hypothalamic neurons by NO- cGMP signal pathway

Objective To study the effects of nitric oxide on Ca2+-activated K+ (KCa) channels in the hypothalamus neurons of newborn SD rats. Methods The data were recorded using inside-out or cell-attached configuration of patch-clamp technique and the kinetic changes of KCa channels are compared before and after 100 μmol/L sodium nitroprusside (SNP) was added into the bathing solution. Results When 100 μmol/L SNP was added to the bathing solution in cell-attached configuration, the open probability of the KCa channels increased from (7.3±1.5)% to (40.2±6.5)%, open time from (7.12±1.41) ms to (15.34±3.45) ms, frequency from (11.3±3.5) Hz to (26.6±4.2) Hz. Conclusion NO-cGMP signal pathway could greatly increase the open probability of the channels as a result of both the prolongation of open period and increase of open frequency, but the pathological or physiological roles it may play require further study.