THE MODULATION OF DOPAMINE-RECEPTORS IN RAT STRIATUM

In the last decades, the contribution given by basic electrophysiology to the understanding of the nigrostriatal pathway in mammals has been rather important. The main results obtained by our group will be revi sed in this short review. The most common responses produced by dopami ne (DA) on the principal striatal cells (the medium spiny neurons) are the modulation of the corticostriatal synaptic transmission and the d ecrease of voltage-dependent inward conductances. After blockade of DA transmission, both spontaneous and cortically driven glutamatergic po stsynaptic potentials were inhibited by the selective activation of DA D2 receptors. In naive animals, the DA-mediated inhibition of postsyn aptic firing activity was mediated by D1 receptor activation. Neverthe less, the two main subclasses of DA receptors seemed to cooperate in t he formation of the long-term depression (LTD) of excitatory synaptic transmission in the striatum. The excitotoxic hypothesis of neurodegen eration has further stimulated our interest towards the study of the i nteractions between DA and other neurotransmitters into the basal gang lia.