Dopamine — Glutamate Interactions

Dopamine (DA) and glutamate interact in the brain on a number of different levels. In this chapter we will illustrate both interneuronal and intraneuronal interactions of the DA and glutamate neurotransmitter systems, ranging from reciprocal release regulation of neurotransmitters to an interactive control of membrane depolarization and gene expression. Although many of these interactions are reciprocal, our approach in this review will be to consider the glutamate system to function as the prime mover, while the DA system provides a strong modulatory influence on responses mediated by glutamate release or activation of glutamate receptors. The characteristics of the modulation by the DA system depend on a number of factors. These include, but certainly are not limited to, the DA and glutamate receptor subtypes involved, the baseline activity-state of the neuron, the location of the receptors on pre- and/or postsynaptic elements, and endogenous concentrations of glutamate and DA. In our view a very important factor is receptor subtype. The combinations of DA and glutamate receptor subtypes activated determines, to a large extent, the outcome of the interaction. Thus, depending on the subtypes of DA and glutamate receptors involved, the interactions can be cooperative or opposing. This chapter will review the present knowledge of the different levels and types of interaction between both neurotransmitter systems.