[Effects of 7-bromoethoxybenzene-tetrahydro-palmatine on isolated working guinea pig heart]

The effective period of isolated working guinea pig heart perfused with Tris-sodium-pyruvate solution (Tris-SP) was shown to be 70 min. Perfluorotributylamine at a concentration of 0.5% added to Tris-SP prolonged the effective time to 90 min. 7-Bromoethyoxybenzene-tetrahydropalmatine (EBP) 10 mumol/L, and prazosin 0.1 mumol/L showed no obvious influence on the parameters in the isolated working guinea pig heart. Methoxamine 1 mumol/L and dopamine 1 mumol/L produced marked changes on LVP, ABF, +/- dp/dtmax and T-CO. It is suggested that the alpha 1-adrenoceptor was partially associated with the positive chronotropic action of the heart. Effects of methoxamine and dopamine on the parameters were antagonized by EBP. It shows that the antagonistic affects of EBP on methoxamine and dopamine are concerned with its antagonistic effect on alpha 1-adrenoceptor and dopamine receptor. This is consistent with previous results in rabbit aortic strips and rat anococcygeus muscles.