摘要
目的:研究组织胺H2受体阻断剂-西米替丁(CMT)对离体豚鼠心房肌动作电位和收缩活动的影响。方法:应用微电极技术和机械收缩描记方法。结果:100μmol/L以上浓度CMT可明显降低豚鼠心房肌动作电位幅度、减慢0期最大除极速率、延长动作电位时程和有效不应期,其作用呈明显浓度依赖性;CMT浓度依赖性地抑制豚鼠右心房肌收缩,使最大收缩幅度降至正常值的54%,但对左心房肌收缩无明显影响。结论:CMT对豚鼠右心房肌有明显抑制作用,其机制可能是通过H2受体,阻断Na+、K+、Ca2+通道所实现的。
Objective:To study the effects of Cimetidine(CMT) on electric and mechanical activities of guinea pig atrial muscles.Methods:Micro electrode technique and mechanical recording of muscle contraction were adopted in the study.Results:CMT (≥100μmol/L) decreased action potential amplitude (APA),maxium rate of rise of phase O (V max ),prolonged action potential duration (APD) and effective refractory period (ERP) in a dose dependent manner.CMT depressed the contraction of right atrial muscle of guinea pig dose dependently, the maximum contraction amplitude was decreased to 54% of control, but had no significant effect on contraction of left atrial muscles.Conclusion:CMT affected the action potential and contraction of guinea pig atrial muscles by antaganizing histamine H 2 receptor and reducing activities of Na + ,K + and Ca 2+ channels.
出处
《河北医科大学学报》
CAS
1998年第6期331-334,共4页
Journal of Hebei Medical University
关键词
西米替丁
药效学
心肌收缩
动作电位
Cimetidine/pharm
myocardial contraction/drug eff
heart atrium
action potentials
guinea pig