Glutamate-Dopamine Interactions in Striatum and Nucleus Accumbens of the Conscious Rat During Aging

In this chapter we review the interaction of glutamate and dopamine in striatum and nucleus accumbens of the conscious rat during aging. We studied the effects of increasing concentrations of endogenous glutamate (obtained by blocking its reuptake) on the extracellular concentrations of dopamine in striatum and nucleus accumbens in the young rat. It was found that increasing concentrations of glutamate correlated significantly with increasing concentrations of dopamine in both structures. The increase of dopamine were significantly reduced after blockade of NMDA and AMPA/kainate glutamate receptors, suggesting that the increase of dopamine was mediated by glutamate. The interaction glutamate/dopamine showed a significant age-related decrease in nucleus accumbens but not in striatum. It is suggested that the interaction glutamate-dopamine represents a balanced input to the GABA neuron in the striatum and nucleus accumbens and that during aging this balance is disrupted.