Effects of atriopeptin III on isolated perfused rat heart

In order to investigate the mechanism by which atriopeptin(AP)lowers cardiacoutput,we observed the effects of AP Ⅲ on isolated perfused rat heart with workingheart perfusion system,thus both neural and humoral influences eliminated.Itwas found that 10 n mol/L AP Ⅲ decreased cardiac output,meanwhile myocardialcontractility and coronary blood flow reduced slightly;40 n mol/L AP Ⅲsignificantly inhibited the heart function,with indices of stroke volume index,cardiac index,coronary blood flow,left ventricular pressure and its differentialall decreased markedly.The results suggested a direct inhibitory effect of AP Ⅲon rat heart.It was further speculated that the decrease of coronary blood flowinduced by AP Ⅲ might be responsible for such an inhibition.