INTRASTRIATAL TAURINE INCREASES STRIATAL EXTRACELLULAR DOPAMINE IN A TETRODOTOXIN-SENSITIVE MANNER IN RATS

In vivo effects of locally administered taurine on striatal dopamine r elease and metabolism were studied by microdialysis in freely moving r ats. Concentrations of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC ) and homovanillic acid (HVA) in striatal dialysates were quantified b y high pressure liquid chromatography (HPLC) using electrochemical det ection. Infusion of 150 mM taurine into the striatum for 2 h induced a 2.5-fold increase in the extracellular dopamine concentration, Extrac ellular DOPAC concentration increased nearly 2-fold. Taurine infusion initially decreased HVA to 70% but afterwards increased it to 140% of the control. When taurine was infused simultaneously with 1 mu M tetro dotoxin starting 60 min after tetrodotoxin, the output of dopamine did not differ from that in the presence of tetrodotoxin alone. Tetrodoto xin abolished the effects of taurine on dopamine metabolites as well. Tetrodotoxin-sensitivity of the effects of taurine on dopamine and its metabolites suggests that intrastriatal taurine elevates extracellula r dopamine by releasing it from neuronal pool.