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 administered phencyclidine (PCP, 10 mg/kg) on the extracellular levels of dopamine, dihydroxyphenylacetate (DOPAC), homovanillate (HVA), 5-hydroxyindolacetate (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 was studied in both anesthetized rats with long and short probe implantation periods and in conscious rats with a long probe implantation period. PCP significantly increased the extracellular levels of dopamine in all experimental groups, though the post-implantation interval and anesthesia modulated the degree of increase. PCP increased 5-HIAA levels in both conscious and anesthetized rats after a long post-implantation period and HVA only in anesthetized rats after a long post-implantation 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.