[Biochemical effects of psychotropic drugs in central nervous system (author's transl)].

Studies on the biochemical effects of clinically used psychotropic drugs in brain have shown that they all exert their action by a direct or indirect interference with synaptic transmission. Thus, animal studies in vivo and in vitro have shown that the clinical efficacy of antipsychotic drugs correlates with their inhibitory action on dopamine receptors. In vivo these compounds enhance dopamine turnover in the brain and in vitro they inhibit the dopamine sensitive adenylate cyclase and the binding of dopamine to its receptor at neuronal membranes. Tricyclic antidepressants are drugs which have effects on many transmitter systems. No specific biochemical action has been found which is closely correlated with their clinical potency. However, it appears that a stimulation of the function of the noradrenergic system might have some clinical relevance. Benzodiazepines exert their pharmacological activity in the CNS by interacting with a brain specific receptor. This receptor appears to be part of a larger complex including a GABA receptor and the chloride conductance mechanism associated with the GABA receptor. By binding to their receptor, benzodiazepines appear to enhance the sensitivity of the GABA receptor, thus indirectly potentiating GABA-ergic neurotransmission in the brain.