Effects of isoprenaline, phenylephrine on heart and influence of nifedipine on these effects

Abstract

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-niediated 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.

Keywords

isoprenaline / phenylephrine / nifedipine / myocardial contraction / myocardial relaxation / slow channel

References

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