氯化汞对豚鼠心室肌电机械活动的影响

Effects of mercuric chloride on electrical and mechanical activities of myocardium in guinea pigs

目的：观察氯化汞（ＨｇＣｌ２）对离体豚鼠乳头状肌的电生理作用。方法：采用心肌细胞内固定微电极技术。结果：ＨｇＣｌ２１～５０μｍｏｌ·Ｌ－１对豚鼠乳头状肌动作电位和收缩力的影响，具有剂量依赖性。ＨｇＣｌ２５μｍｏｌ·Ｌ－１使ＡＰＡ和Ｖｍａｘ降低，动作电位时程及ＥＲＰ缩短，心肌收缩力加强。用药物阻滞钙通道，ＨｇＣｌ２改变动作电位的ＡＰＡ，Ｖｍａｘ，ＡＰＤ。ＨｇＣｌ２１０～２０μｍｏｌ·Ｌ－１增加哇巴因诱发的震荡后电位，使触发电活动增强。结论：ＨｇＣｌ２对心脏的毒性，可能通过其使心肌细胞内钙超负荷。

AIM:The effect of mercuric chloride (HgCl 2) 1￣50 μmol·L -1 on transmembrane potentials and contraction of isolated papillary muscles in guinea pigs was studied. METHODS:The conventional intracellular microelectrodes techniques were used. RESULTS:Mercuric chloride 5 μmol·L -1 decreased the amplitude and V max of action potential, shortened the duration of action potential and functional refractory period, the force of contraction was increased. After the calcium channel was blocked, mercuric chloride changed the APA, V max and APD of the AP. Mercuric chloride 10￣20 μmol·L -1 increased the amplitude of osillary after potential induced by ouabain and enhanced the trigged activity. CONCLUSIONS:Mercuric chloride could induced Ca 2+ overload of cells.