Halbach S, Schönsteiner G, Vierling W
Institut für Toxikologie, Gesellschaft für Strahlen- und Umweltforschung, Neuherberg, F.R.G.
Eur J Pharmacol. 1989 Aug 22;167(2):255-64. doi: 10.1016/0014-2999(89)90586-4.
The effects of four organic mercury compounds (methylmercuric chloride; bromomercurihydroypropane, BMHP; chlormerodrin; p-chloromercuribenzoic acid, PCMB) on mechanical and electrical functions of guinea-pig papillary muscles were investigated. An initial decline in contraction force was followed by a transient positive inotropic response. The first was accompanied by a shortening of the action-potential duration and by a reduction of the depolarization velocity and the duration of the Ca2+-dependent slow response. The latter was characterized by an indirect component (release of noradrenaline) and by a direct component, which was dependent on the stimulation rate and on the extracellular concentration of Na+ and K+. The direct positive effect, therefore, was likely to have resulted from inhibition of the sarcolemmal Na+ + K+-ATPase. This notion was confirmed by experiments with isolated membrane particles. The prevalence of the negative or positive inotropic action of these compounds could be ascribed to their lipophilic or hydrophilic properties, respectively.
研究了四种有机汞化合物（氯化甲基汞；溴汞基羟基丙烷，BMHP；氯汞君；对氯汞苯甲酸，PCMB）对豚鼠乳头肌机械和电功能的影响。收缩力最初下降，随后出现短暂的正性肌力反应。前者伴随着动作电位时程缩短、去极化速度降低以及钙依赖性慢反应时程缩短。后者的特征是间接成分（去甲肾上腺素释放）和直接成分，直接成分取决于刺激频率以及细胞外钠和钾的浓度。因此，直接的正性作用可能是由于肌膜钠钾ATP酶受到抑制所致。用分离的膜颗粒进行的实验证实了这一观点。这些化合物负性或正性肌力作用的普遍程度可分别归因于它们的亲脂性或亲水性。
