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目的:研究蜂毒肽(Mel)对离体豚鼠乳头状肌的影响。方法:观察Mel对豚鼠乳头状肌基本生理特性的影响,并应用标准玻璃微电极技术记录快反应动作电位(FAP)和慢反应动作电位(SAP)。结果:Mel(0.5,3μmol/L)显著增强乳头状肌收缩力,Mel(5μmol/L)在增强收缩力之前可出现短暂的抑制作用。Mel(0.5,3,5μmol/L)可显著缩短功能性不应期,在一定浓度下(Mel 3,5μmol/L)可升高肾上腺素诱发的自律性,使时间-兴奋曲线上移(Mel 3μmol/L)。Mel(0.3,5μmol/L)可显著缩短FAP的动作电位时程(APD),减小动作电位幅度(APA)和静息电位(RP)。Mel 0.8μmol/L可减小SAP的APA和RP,仅缩短APD_(20)和APD_(50),对APD_(90)无影响。结论:Mel增强豚鼠乳头状肌收缩性和自律性,缩短不应期,降低兴奋性,缩短APD,减小APA和RP。
Objective: To study the effect of melittin on guinea pig papillary muscles. Methods: The effects of Mel on the basic physiological characteristics of guinea pig papillary muscles were observed. Fast response action potential (FAP) and slow response action potential (SAP) were recorded by standard glass microelectrode technique. Results Mel (0.5, 3μmol / L) significantly enhanced the contractility of papillary muscles, and Mel (5μmol / L) showed short-term inhibition before enhancing contractility. Mel (0.5, 3, 5μmol / L) significantly shortened the functional refractory period. At a certain concentration (Mel 3,5 μmol / L), adrenaline-induced autonomic regulation was increased and the time- 3 μmol / L). Mel (0.3, 5μmol / L) significantly shortened the action potential duration (APD) and decreased the action potential amplitude (APA) and resting potential (RP) of FAP. Mel 0.8 μmol / L can reduce APA and RP of SAP, shorten APD_ (20) and APD_ (50), but have no effect on APD_ (90). CONCLUSION: Mel enhances contractility and self-discipline of guinea pig papillary muscles, shortens refractory period, reduces excitability, shortens APD and decreases APA and RP.