利多卡因对大鼠海马神经元L-型Ca^(2+)通道电流的影响

Effects of lidocaine on currents of L-type Ca^(2+) channels in CA1 pyramidal neurons in hippocampus of adult rats

目的观察不同浓度利多卡因对成年大鼠海马CA1区锥体细胞L-型Ca2+通道电流的影响,以探讨其对中枢神经的作用。方法采用酶加机械分离的方法,急性分离成年大鼠海马CA1区锥体细胞。运用膜片钳细胞贴附模式技术,记录0、2、4、8、16、32μg/ml的利多卡因对L-型Ca2+通道电流幅度和电导的影响。结果不同浓度的利多卡因不影响单通道的单一电流幅度,也不影响L-型Ca2+通道的单通道电导。低浓度利多卡因(2、4μg/ml)对L-型Ca2+通道的整体平均电流无明显影响;浓度为8、16、32μg/ml时,整体平均电流分别为(0.80±0.09)、(0.67±0.07)、(0.37±0.05)pA(与对照浓度比较,P<0.05)。结论利多卡因影响成年大鼠海马CA1区锥体细胞L-型Ca2+通道电流,随着浓度的增加表现为先兴奋后抑制。

Objective To investigate the effects of lidocaine on the currents of L-type Ca^2＋ channels in CA1 pyramidal neurons in the hippocampus of adult rats. Methods Adult rat hippocampal CA1 pyramidal neurons were obtained by a combination of mechanical and enzymatic means. Cellattached mode of patch clamp technique was used to record L-type Ca^2＋ channel currents. Results No significant differences were seen in single-channel unitary current amplitude at any voltage or in slope conductance before and after infusing lidocaine. Average total patch current in patches was （0.50± 0. 02） pA in control and （0.80±0.09） pA in concentration of 8 μg/ml （P〈0.05） ,（0.67±0.07） pA （16 μg/ml, P〈0. 05） ,then （0.37±0.05） pA （32 μg/ml P〈0.05）. Conclusion Effects of lidocaine on currents of L-type Ca^2＋ channels in CA1 pyramidal neurons in the hippocampus of adult rats presented the two-phases action of excitation and inhibition.