Zhang X M, Yang S, He X J, Zheng P, Jiang M H
Department of Pharmacology, School of Pharmacy, State Key Laboratory of Medical Neurobiology, Shanghai Medical University, Shanghai 200032, China.
Acta Pharmacol Sin. 2000 Sep;21(9):841-4.
To examine the effects of melittin (Mel), the major component of bee venom, on delayed rectifier K+ current (Ik), inward rectifier K+ current (Ikl) and action potential (AP) in guinea pig ventricular myocytes.
Ik, Ikl, and AP were recorded using the whole-cell patch-clamp technique.
The action potential duration (APD) was shortened by Mel in a concentration-dependent manner. Mel 0.05, 0.1, 0.2 mumol.L-1 shortened APD50 from (520 +/- 55) to (459 +/- 91) (n = 5, P > 0.05), (385 +/- 102) (n = 5, P < 0.01), and (281 +/- 81) ms (n = 5, P < 0.01), respectively; and APD90 from (613 +/- 96) to (536 +/- 93) (n = 5, P > 0.05), (467 +/- 96) ms (n = 5, P < 0.01), and (354 +/- 95) ms (n = 5, P < 0.01), respectively. Mel increased the amplitude of Ik also in a concentration-dependent manner. Mel 0.05, 0.1, 0.2 mumol.L-1 increased Ik from (295 +/- 109) to (371 +/- 142) (n = 5, P < 0.05), (467 +/- 180) (n = 5, P < 0.05), (552 +/- 248) pA (n = 5, P < 0.05), respectively at testing potential of + 40 mV. But no significant effect of Mel on Ikl was observed at these concentrations.
Mel significantly increased Ik in a concentration-dependent manner which contributed to shortening of APD.
研究蜂毒主要成分蜂毒肽（Mel）对豚鼠心室肌细胞延迟整流钾电流（Ik）、内向整流钾电流（Ikl）及动作电位（AP）的影响。
采用全细胞膜片钳技术记录Ik、Ikl和AP。
Mel可浓度依赖性地缩短动作电位时程（APD）。Mel 0.05、0.1、0.2 μmol·L-1分别将APD50从（520±55）缩短至（459±91）（n = 5，P>0.05）、（385±102）ms（n = 5，P<0.01）和（281±81）ms（n = 5，P<0.01）；将APD90分别从（613±96）缩短至（536±93）（n = 5，P>0.05）、（467±96）ms（n = 5，P<0.01）和（354±95）ms（n = 5，P<0.01）。Mel也可浓度依赖性地增加Ik的幅度。在测试电位为+40 mV时，Mel 0.05、0.1、0.2 μmol·L-1分别将Ik从（295±109）增加至（371±142）（n = 5，P<0.05）、（467±180）（n = 5，P<0.05）、（552±248）pA（n = 5，P<0.05）。但在这些浓度下未观察到Mel对Ikl有显著影响。
Mel可浓度依赖性地显著增加Ik，这有助于缩短APD。
