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目的:观察双苯氟嗪(Dip)对豚鼠心室肌细胞L-型钙电流(I_(Ca-L))的影响。方法:酶解法制备单个心室肌细胞。应用全细胞膜片箝技术记录豚鼠单个心室肌细胞钙电流。结果:在0.3-30μmol/L范围内,Dip可浓度依赖性地降低电压依赖性激活I_(Ca-L)峰值,被Dip 3μmol/L所抑制的I_(Ca-L)在冲洗5min后可得到部份恢复。但Dip对I_(Ca-L)的电压依赖特征,最大激活电压,以及I_(Ca-L)稳态激活无明显影响。在Dip3μmol/L存在下,半数激活电压(V_(0.5))和斜率参数(к)与对照组相比,差异均无显著性。V_(0.5)分别为(-12.8±1.7)mV和(-13.2±2.4)mV,к分别为(7.1±0.4)mV和(7.5±0.5)mV(P>0.05)。Dip3μmol/L可明显使钙电流稳态失活曲线左移,加速钙通道电压依赖性稳态失活。V_(0.5)分别为(-19.7±2.4)mV和(-31±6)mV,к分别为(3.6±0.3)mV和(1.8±0.2)mV(P<0.05).Dip 3μmol/L还使I_(Ca-L)从失活状态下的恢复明显减慢。结论:Dip主要作用于L-型钙通道的失活状态,加速钙通道失活,并使其从失活状态下恢复减慢,从而抑制I_(Ca-L)。
Objective: To observe the effect of Diphenhydramine on L-type calcium current (I_ (Ca_ L)) in guinea pig ventricular myocytes. Methods: Enzymatic method was used to prepare single ventricular myocytes. Whole cell patch clamp technique was used to record the calcium current in guinea pig single ventricular myocytes. Results: In the range of 0.3-30μmol / L, Dip could decrease the peak of voltage-dependent activation I_ (Ca-L) in a concentration-dependent manner. I_ (Ca-L) inhibited by Dip 3μmol / Partial recovery. But Dip had no significant effect on I_ (Ca-L) voltage dependence, maximum activation voltage, and I_ (Ca-L) homeostasis. In the presence of Dip3μmol / L, the half activation voltage (V_ (0.5)) and the slope parameter (к) were not significantly different from the control group. The V_ (0.5) values were (-12.8 ± 1.7) mV and (-13.2 ± 2.4) mV, respectively, and were respectively (7.1 ± 0.4) mV and (7.5 ± 0.5) mV (P> 0.05). Dip3μmol / L can obviously shift the steady-state inactivation curve of calcium current to the left and accelerate the voltage-dependent steady-state inactivation of calcium channel. The V_ (0.5) values were (-19.7 ± 2.4) mV and (-31 ± 6) mV and (3.6 ± 0.3) mV and (1.8 ± 0.2) mV, respectively I_ (Ca-L) recovery from inactivation significantly slowed down. Conclusion: Dip mainly acts on the inactivation of L-type calcium channels, accelerating the inactivation of calcium channels and slowing down the recovery from inactivation, thereby inhibiting I-Ca-L.