Dopamine Agonists in the Treatment of Schizophrenia

Abstract

Behavioral, neurochemical, ligand binding, and single cell unit recording studies suggest the existence of two distinct classes of dopamine (DA) receptors: autoreceptors, which are present on the membranes of dopamine neurons, and postsynaptic receptors located on the neurons with which dopamine neurons synapse. Various pharmacological studies have suggested an overactivity of dopaminergic neurons in schizophrenic patients, however, studies on the concentrations of dopamine metabolites in cerebrospinal fluid (CSF) and post-mortem brain tissue, and clinical studies with schizophrenic patients who are free of drugs do not support this interpretation. Attention has therefore turned to the studies on the central dopamine receptors in schizophrenia. The use of binding techniques with tritiated ligands to study dopamine receptor density in post-mortem brain tissue has produced a number of interesting results. At present, it is accepted that the density of dopamine receptors in post-mortem brain tissue from schizophrenic patients is significantly increased in the striatum and in the nucleus accumbens.