Enhancing effect of taurine on the rat caudate spindle. I: Interaction of taurine with the nigro-striatal dopamine system.

We studied the effects of taurine on the caudate spindle in rats and compared the findings with those of gamma-aminobutyric acid (GABA) when these compounds were microinjected into the bilateral striatum. Three micrograms of taurine was without effect, whereas 10 and 30 micrograms of taurine enhanced the spindle in a dose-dependent manner. GABA (3-100 micrograms) had no significant effect. Apomorphine (0.5 mg/kg) and methamphetamine (0.5 mg/kg) given intravenously to pargyline-pretreated rats suppressed the spindle. The suppressing effects of these drugs were reduced by taurine (3 micrograms) at the dose which, per se, did not affect the spindle. These results suggest that taurine may decrease the activity of striatal dopaminergic neurons and enhance the caudate spindle.