[Functional aspects of the interaction between benzodiazepines and their central receptors]

The present review deals with animal data substantiating the functional significance of central benzodiazepine (BZD) receptors both in the pharmacological effects of BZD and, in a more general way, in the control of anxiety-related states or behavior. Several experiments including those dealing with BZD antagonists (Ro 15-1788, beta-carbolines) reveal that an excellent correlation exists between BZD receptors occupancy and the intensity of various pharmacological actions of BZD or of agents known to bind to these receptors. Furthermore, BZD binding can be modified by subjecting laboratory animals to chronic BZD administration, convulsant treatments or anxiogenic situations. Finally, the reciprocal influence that appears between BZD receptors and GABA receptors can be relevantly associated with many pharmacological action of BZD. Such a notion further reinforce the functional role(s) that BZD receptors may have within the brain. Taken together these data suggest that the plasticity of BZD receptors is in fact similar to that observed for other receptors, the corresponding endogenous neurotransmitter of which is already identified.