RÉSUMÉ
Objective To explore the nechanism of the interaction between K-opioid receptor and ? adrenal receptor. Method The effects of u50 488H on L-type calcium currents in the normal and hypoxic rat ventricular myocytes were studied by using whole-cell patch clamp technique. Results The basal as well as Isoproterenol-stimulated I_ Ca,L were inhibited by U50,488H in a dose-dependent manner in normal rat ventricular myocytes. In the hypoxic rat ventricular myocytes,the inhibitory effect of U50,488H was decreased. U50,488H had no significant effect on Forkolin-stimulated I_ Ca,L . Conclusion The results indicated that the negative modulation of ?-opioid receptor on ?-adrenoceptor was attenuated in the hypoxic ventricular myocytes,and the target of U50,488H on ?-adrenergic system might be situated between ?-adrenoceptor and adenylate cyclase.