In a perfused isovolumetrically contracting rat heart model, the effects of isoprenaline(IPN) and phenylephrine (PE) on myocardial contraction and relaxation were investigated,and the influence of nifedipine on these ...In a perfused isovolumetrically contracting rat heart model, the effects of isoprenaline(IPN) and phenylephrine (PE) on myocardial contraction and relaxation were investigated,and the influence of nifedipine on these effects was studied. Both IPN and PE increased the myocardial contraction and improved its relaxation, but some differences existed.Nifedipine (10 nmol/L)substantially inhibited the PE-mediated inotropic effect, but in case of IPN-mediated inotropic ones, it did not.It was assumed that there may be various types of slow channels, one was activated by IPN,and the other, by PE.展开更多
文摘In a perfused isovolumetrically contracting rat heart model, the effects of isoprenaline(IPN) and phenylephrine (PE) on myocardial contraction and relaxation were investigated,and the influence of nifedipine on these effects was studied. Both IPN and PE increased the myocardial contraction and improved its relaxation, but some differences existed.Nifedipine (10 nmol/L)substantially inhibited the PE-mediated inotropic effect, but in case of IPN-mediated inotropic ones, it did not.It was assumed that there may be various types of slow channels, one was activated by IPN,and the other, by PE.
