Implication of Substance P in myocardial contractile function during ischemia in rats

► Substance P and norepinephrine were increased in myocardium at 15-60 min of CAO. ► Antagonism of NK-1 receptor increased + dp/dt and decreased − dp/dt following CAO. ► Substance P significantly increased LVEDP following CAO. ► Substance P attenuated the contractility and diastolic functions of norepinephrine. ► Substance P regulates cardiac functions via modulation of adrenergic activity.