摘要
应用细胞内固定微电极技术,观察了不同浓度CdCl_2对豚鼠右心室乳头状肌快、慢反应AP及Fc的影响.结果表明20μmol/L CdCl_2对快反应APA及V_(max)无显著影响,但却抑制Fc;100和500μmol/L对上述各参数均呈抑制作用.各种剂量的CdCl_2对慢反应电位均可降低APA及V_(max),抑制Fc,缩短APD_(50)及APD_(90),对抗CaCl_2所致的正性频率作用.提示低剂量Cd使心肌细胞兴奋收缩脱耦联.可能有抗心肌Ca^(2+)流效应.
The effects of cadmium chloride on action potentials of the guinea pig papillary muscle cells were studied by using the conventional microelectrode methods.The results showed that CdCl2(20μmol/L)produced a negative chronotropic effect and a decrease of APD50 and APD90 but had no effect on APA and Vmax Cadmium chloride(100μmol/L and 500μmol/L)showed inhibitory effecton many parameters of the action potentials including APA,Vmax,Fc,APD50 and APD90 The effects of cadmium chloride on slow action potential and contractile force(Fc)of the preparations in which the Na+channels were inactivated by partial depolarization by increasing the concentration of K+to 25.4 mmol/L were observed.APA,Vmax,Fc,APD50 and APD90 of slow action potential were decreased by cadmium chlo- ride.Furthermore,CdCl2 antagonized the positive chronotropic action to Ca2+(3.3 mmol/L)in the guinea pig right auricle.The results mentioned above suggest that cadmium chloride may make the papillary muscle cells excitation-contraction uncoupling and in-hibit Ca2+ conductance through Ca2+ channel.
出处
《中国药理学与毒理学杂志》
CAS
CSCD
北大核心
1990年第1期67-70,共4页
Chinese Journal of Pharmacology and Toxicology
关键词
镉
动作电位
收缩力
乳头状肌
cadmium
action potentials
contractile force
papillary muscle
anti-calcium