藻酸双酯钠对豚鼠乳头状肌动作电位和收缩的抑制作用

目的 观察藻酸双酯钠（ＰＳＳ）对豚鼠乳头状肌动作电位和收缩力（ＦＣ）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（ＦＡＰ）和慢反应动作电位（ＳＡＰ）。结果：ＰＳＳ（≥５０ｍｇ．Ｌ＾－１）浓度依赖性地使ＦＣ减弱和ＦＡＰ原动作电位时程（ＡＰＤ）缩短，但对静息电位和动作电位幅度（ＡＰＡ）及０期最大除极速率（Ｖｍａｘ）均无显著影响。ＰＳＳ（≥１５ｍｇ．Ｌ＾－１）浓度依赖性地使ＢａＣｌ

Inhibitory actions of polysaccharide sulfate on action potentials and contraction of papillary muscles in guinea pigs.

AIM: To examine the effects of polysaccharide sulfate (PSS) on the action potentials and contractile force in guinea pig papillary muscles. METHODS: Using intracellular microelectrode to record fast (FAP) and slow (SAP) action potentials. RESULTS: PSS (> or = 50 mg.L-1) caused concentration-dependent decreases in 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 (Vmax). The Vmax, APA, and APD of BaCl2-induced SAP were concentration-dependently decreased by PSS (> or = 15 mg.L-1) and the effects were antagonized by isoprenaline (1 mumol.L-1). The APA and APD of isoprenaline-induced SAP were decreased by PSS (> or = 15 mg.L-1) in a concentration-dependent manner and the effects were attenuated by elevation of extracellular Ca2+ concentration. CONCLUSION: PSS selectively inhibited the slow inward current.