甘糖酯对豚鼠乳头状肌动作电位和收缩的抑制作用

Inhibitory actions of propylene glycol mannate sulfate on action potentials and contraction of papillary muscles in guinea pigs

目的 :观察甘糖酯 (PGMS)对豚鼠乳头状肌动作电位和收缩力的影响。方法 :利用细胞内微电极技术记录豚鼠乳头状肌的快反应动作电位、慢反应动作电位及收缩力。结果 :PGMS浓度依赖性地使FAP的动作电位时程缩短和FC减弱 ,但对静息电位和动作电位幅度及 0期最大除极速率均无显著影响。PGMS浓度依赖性地使BaCl2 诱发的SAP的Vmax和APA降低 ,APD缩短。PGMS浓度依赖性的使异丙肾上腺素诱发的SAP的APA降低 ,APD缩短 ,FC减弱。提高细胞外Ca2 + 浓度后 ,以上各项参数基本恢复正常。结论

AIM: To examine the effects of propylene glycol mannate sulfate (PGMS) on the action potentials and contractile force in guinea pig papillary muscles. METHODS: An intracellular microelectrode was used to record fast (FAP) and slow (SAP) action potentials. RESULTS: PGMS concentration dependently decreased the contractile force and the action potential duration (APD) of FAP without affecting the resting potential (RP), action potential amplitude (APA), and maximal upstroke velocity (V max ). The V max , APA, and APD of BaCl 2 induced SAP were concentration dependently decreased by PGMS and the effects were antagonized by isoprenaline. The APA and APD of isoprenaline induced SAP were decreased by PGMS in a concentration dependent manner and the effects were attenuated by elevation of intracellular Ca 2+ concentration. CONCLUSLON: PGMS selectively inhibits the slow inward current.