EXTRACELLULAR ASPARTATE CONCENTRATION INCREASES IN NUCLEUS-ACCUMBENS AFTER COCAINE SENSITIZATION

Rats were sensitized to cocaine (15 mg/kg, i.p.) by 6 daily injections followed by a 48 h withdrawal prior to cocaine challenge. Involvement of excitatory amino acids in behavioral sensitization was assessed by comparing extracellular levels of aspartate and glutamate in the core of the nucleus accumbens in response to the first cocaine injection a nd the final cocaine challenge. Intracerebral microdialysis of the nuc leus accumbens in freely moving awake rats allowed the comparison of b ehavioral stare with extracellular aspartate and glutamate concentrati ons. Increased nucleus accumbens extracellular concentration of aspart ate, but not glutamate, was observed in rats exhibiting behavioral sen sitization to cocaine.