[水杨酸盐对大鼠下丘神经元钾通道的抑制作用]
[Inhibition of salicylate on potassium channels in rat inferior colliculus neurons].
作者信息
Liu Yan-xing, Li Xue-pei, Liu Jun-xiu, Shi Ge-ming, Lu Hong, Ma Chang-sheng
机构信息
Department of Otorhinolaryngology, Third affiliated Hospital,Peking University, Beijing 100083, China.
出版信息
Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi. 2005 Nov;40(11):835-9.
OBJECTIVE
To understand what role of the transient outward potassium channels and the delayed rectifier potassium channels play in the mechanism of salicylate-induced tinnitus.
METHODS
The effects of salicylate on the transient outward potassium channels and the delayed rectifier potassium channels in freshly dissociated inferior colliculus neurons of rats were studied, using the whole-cell voltage clamp method.
RESULTS
Salicylate blocked the transient outward potassium current (I(K(A and the delayed rectifier potassium current (I(K(DR in concentration-dependent manner (0.1-1 mmol/L). The IC50 values for the blocking action of salicylate on I(K(A)) and I(K(DR)) were 2.27 and 0.80 mmol/L, respectively. At a concentration of 1 mmol/L, salicylate did not shift the activation and inactivation curves of I(K(A)), but significantly shifted the activation and inactivation curves of I(K(DR)) negatively by approximately 11 mV and 24 mV.
CONCLUSIONS
Salicylate inhibits both I(K(A)) and I(K(DR)) in rat inferior colliculus neurons but only significantly affects the activation and inactivation kinetics of I(K(DR)). Effects of I(K(A)) and I(K(DR)), especially I(K(DR)), by salicylate may play an important role in salicylate-induced tinnitus.
目的
了解瞬时外向钾通道和延迟整流钾通道在水杨酸盐诱导耳鸣机制中所起的作用。
方法
采用全细胞膜片钳技术，研究水杨酸盐对大鼠新鲜分离的下丘神经元中瞬时外向钾通道和延迟整流钾通道的影响。
结果
水杨酸盐以浓度依赖方式（0.1 - 1 mmol/L）阻断瞬时外向钾电流（I(K(A))）和延迟整流钾电流（I(K(DR))）。水杨酸盐对I(K(A))和I(K(DR))阻断作用的半数抑制浓度（IC50）值分别为2.27和0.80 mmol/L。在1 mmol/L浓度下，水杨酸盐未使I(K(A))的激活和失活曲线发生移位，但使I(K(DR))的激活和失活曲线分别显著负向移位约11 mV和24 mV。
结论
水杨酸盐抑制大鼠下丘神经元中的I(K(A))和I(K(DR))，但仅显著影响I(K(DR))的激活和失活动力学。水杨酸盐对I(K(A))和I(K(DR))，尤其是I(K(DR))的作用可能在水杨酸盐诱导的耳鸣中起重要作用。
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