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目的:研究四氢巴马汀(THP)对豚鼠心室肌细胞膜Ca~(2+)通道的作用。方法:分离豚鼠心室肌细胞,利用膜片箝技术观察、记录心室肌细胞膜跨膜内向钙电流(I_(Ca))。结果:THP灌流5min后明显抑制豚鼠心室肌细胞内向I_(Ca),其作用呈现剂量-效应关系,并具有频率依赖性。0.1,1,10μmol·L~(-1)的THP使I_(ca)从1.15±0.22,0.91±0.18,1.60±0.42nA(control,n=5)分别降低到0.90±0.21(P<0.01),0.56±0.21(P<0.01),0.83±0.21(P<0.05)nA,抑制率分别为22％,38％和48％,THP的作用易于洗脱。峰值电压为0mV,此时THP作用最明显,THP对较高频率刺激产生的电流抑制作用较强,2Hz时的抑制率高于0.1Hz时的抑制率(P<0.01)。结论:THP具有Ca~(2+)通道阻滞作用。
Objective: To investigate the effect of tetrahydropalmatine (THP) on Ca 2+ channel in guinea pig ventricular myocytes. Methods: Guinea pig ventricular myocytes were isolated and observed using the patch clamp technique. The transmembrane inward Ca2 + current (I_ (Ca)) of ventricular myocytes was recorded. Results: After THP perfusion for 5min, the inward I_ (Ca) of guinea pig ventricular myocytes was significantly inhibited. The effect was dose-dependent and frequency-dependent. 0.1, 1, 10μmol·L -1 THP decreased I_ (ca) from 1.15 ± 0.22,0.91 ± 0.18,1.60 ± 0.42nA (control, n = 5) to 0.90 ± 0.21 (P <0.01) , 0.56 ± 0.21 (P <0.01) and 0.83 ± 0.21 (P <0.05) nA respectively. The inhibitory rates were 22%, 38% and 48% respectively. The effect of THP was easy to elute. The peak voltage was 0mV, the effect of THP was the most obvious at this time. THP had a stronger inhibitory effect on the current induced by higher frequency stimulation, and the inhibition rate at 2Hz was higher than that at 0.1Hz (P <0.01). Conclusion: THP has Ca ~ (2 +) channel blockade.