SYSTEMIC PHENCYCLIDINE ADMINISTRATION IS ASSOCIATED WITH INCREASED DOPAMINE, GABA, AND 5-HIAA LEVELS IN THE DORSOLATERAL STRIATUM OF CONSCIOUS RATS - AN IN-VIVO MICRODIALYSIS STUDY

In vivo microdialysis was used to study the effects of systemically ad ministered phencyclidine (PCP, 10 mg/kg) on the extracellular levels o f dopamine, dihydroxyphenylacetate (DOPAC), homovanillate (HVA), 5-hyd roxyindolacetate (5-HIAA), gamma-aminobutyrate (GABA), glutamate, and aspartate in the rat dorsolateral striatum. In order to demarcate the effects of anesthesia, tissue trauma and gliosis, the effect of PCP wa s studied in both anesthetized rats with long and short probe implanta tion periods and in conscious rats with a long probe implantation peri od. PCP significantly increased the extracellular levels of dopamine i n all experimental groups, though the post-implantation interval and a nesthesia modulated the degree of increase. PCP increased 5-HIAA level s in both conscious and anesthetized rats after a long post-implantati on period and HVA only in anesthetized rats after a long post-implanta tion period. Glutamate, aspartate, and DOPAC were not affected by PCP challenge but our study indicated for the first time that systemic PCP elevates extracellular GABA in conscious rats.