ANTAGONISTIC EFFECTS OF BETA-PHENYLETHYLAMINE ON QUINPIROLE-INDUCED AND (-)-SULPIRIDE-INDUCED CHANGES IN EVOKED DOPAMINE RELEASE FROM RAT STRIATAL SLICES

To assess the role of beta-phenylethylamine in aspects of dopamine rel ease, we measured the level of beta-phenylethylamine in the rat striat um after killing the rats by microwave irradiation. We then investigat ed the effect of beta-phenylethylamine on electrically evoked dopamine release from rat striatal slices in vitro. The striatal beta-phenylet hylamine level was 46.5 +/- 3.5 ng/g wet tissue, equivalent to 0.3 mu mol/l. Superfusion with low concentrations of beta-phenylethylamine up to 1 mu mol/l had no effect on spontaneous or electrically evoked dop amine release from striatal slices. Quinpirole reduced the evoked dopa mine release from slices in a concentration-dependent manner. The quin pirole-induced reduction of evoked dopamine release was attenuated 30% by superfusion with 0.3 mu mol/l beta-phenylethylamine. Moreover, the (-)-sulpiride (0.1 mu mol/l)-induced increase in evoked dopamine rele ase was also attenuated by superfusion with 0.3 mu mol/l beta-phenylet hylamine. These data indicate that submicromolar levels of beta-phenyl ethylamine could modify the dopamine autoreceptor mediated changes in evoked dopamine release from rat striatal slices. (C) 1998 Elsevier Sc ience B.V.