DOPAMINE AND SCHIZOPHRENIA. A Theory Revisited and Revised

Evidence is presented for a modulatory role for dopamine in the C.N.S. and for an indirect rather than a direct involvement of dopaminergic systems in the production of schizophrenic symptoms. The fine structure of dopaminergic fibres indicates that a majority of presynaptic boutons are not in close juxtaposition with postsynaptic neuronal membranes. This points to a wider distribution of receptors than localisation to dense postsynaptic membrane. Preliminary studies of receptor localisation support this conclusion, providing indirect evidence for autoreceptors and evidence for localisation, in the glia, of a sub- stantial number of receptors.