【摘要】 本文报告APⅢ对豚鼠心乳头状肌动作电位、收缩力及犬心浦氏纤维Isi的作用。APⅢ于0.1～100nM浓度依赖性地增强豚鼠心乳头状肌的等长收缩张力及延长其APD₉₀和ERP。10nM时作用最明显,F_c提高27.6％,APD₉₀和ERP分别延长23和25ms。对动作电位的其它参数没有明显影响。其正性肌力、延长APD₉₀和ERP等作用,于给药后3 min开始,10 min达最大,维持时间可达30 min。APⅢ 30nM对使犬心浦氏纤维Isi增加18.6％。结果表则,APⅢ对哺乳动物心肌具有直接作用,提示分泌心房肽的器官-心脏也为该物质的靶器官之一。更多还原

【Abstract】 It was reported that atrio peptins possess diuretic, vasodilative, hypo tensive effects and inhibit the release of al dosterone and vasopressin. The effects of synthetic atriopeptin Ⅲ(AP Ⅲ) were studied on the action potential and force of contraction in isolated papillary muscle of guinea pigs as well as slow inward current (Isi) of canine Purkinje fibres.0.1-100 nM APⅢ increased isometric contractile force, action potential duration to 90% repolarization (APD90) and effective refractory period (ERP) in a concentration-dependent manner. At the maximum effect concentraction(by APⅢ 10nM), APD90 and ERP increased by 27.6%, 23 ms and25 ms,respectively. The effects set out at 3 min, reached peak at 10 min, and sustained for 30 min. APⅢ 30 nM increased the peak value of Isi of canine Purkinje fibres by 18.6% of the control.The above mentioned results indicate that AP 1 also possesses a direct action on myocardium. It is of interest that the heart is not only a secretory but also a target organ for atriopeptins, the hormon-like substances.更多还原