Neurochemical research
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Neurochemical research · Aug 1999
Effects of endogenous glutamate on extracellular concentrations of GABA, dopamine, and dopamine metabolites in the prefrontal cortex of the freely moving rat: involvement of NMDA and AMPA/KA receptors.
Using microdialysis, interactions between endogenous glutamate, dopamine, and GABA were investigated in the medial prefrontal cortex of the freely moving rat. Interactions between glutamate and other neurotransmitters in the prefrontal cortex had already been studied using pharmacological agonists or antagonists of glutamate receptors. This research investigated whether glutamate itself, through the increase of its endogenous extracellular concentration, is able to modulate the extracellular concentrations of GABA and dopamine in the prefrontal cortex. ⋯ The NMDA antagonist had no effect on the increase of extracellular GABA, but blocked the decreases of extracellular DOPAC and HVA, produced by PDC. In contrast, the AMPA/KA antagonist blocked the increases of extracellular GABA without affecting the decreases of extracellular DOPAC and HVA produced by PDC. These results suggest that endogenous glutamate acts preferentially through NMDA receptors to decrease dopamine metabolism, and through AMPA/KA receptors to increase GABAergic activity in the medial prefrontal cortex of the awake rat.