Effects of taurine on striatal dopamine transporter expression and dopamine uptake in SHR rats.

Dopaminergic deficits in the prefrontal cortex and striatum have been attributed to the pathogenesis of attention-deficit hyperactivity disorder (ADHD). Our recent study revealed that high-dose taurine improves hyperactive behavior and brain-functional signals in SHR rats. This study investigates the effect of taurine on the SHR striatum by detecting the spontaneous alternation, DA transporter (DAT) level, dopamine uptake and brain-derived neurotrophic factor (BDNF) expression. A significant increase in the total arm entries was detected in both WKY and SHR rats fed with low-dose taurine but not in those fed with high-dose taurine. Notably, significantly increased spontaneous alternation was observed in SHR rats fed with high-dose taurine. Significantly higher striatal DAT level was detected in WKY rats fed with low-dose taurine but not in SHR rats, whereas significantly reduced striatal DAT level was detected in SHR rats fed with high-dose taurine but not in WKY rats. Significantly increased dopamine uptake was detected in the striatal synaptosomes of both WKY and SHR rats fed with low-dose taurine. Conversely, significantly reduced dopamine uptake was detected in the striatal synaptosomes of SHR rats fed with high-dose taurine. Accordingly, a negative correlation was detected between striatal dopamine uptake and spontaneous alternation in SHR rats fed with low or high-dose taurine. Significantly increased BDNF was detected in the striatum of both WKY and SHR rats fed with low or high-dose taurine. These findings indicate that different dosages of taurine have opposite effects on striatal DAT expression and dopamine uptake, suggesting high-dose taurine as a possible candidate for ADHD treatment.