GABA and endorphin mechanisms in relation to the effects of benzodiazepines on feeding and drinking

Behavioural actions of benzodiazepines have a number of significant characteristics. Anxiolytic effects are demonstrable both clinically and experimentally; in addition, there is excellent evidence for a reinforcing effect of these compounds, and a direct involvement in ingestional responses. This review focusses on the effects of benzodiazepines on the latter feeding and drinking responses. A necessary mediator of benzodiazepine action in the central nervous system appears to be the facilitation of inhibitory GABAergic neurotransmission. It follows, therefore, that behavioural consequences of benzodiazepine action may depend crucially on enhanced GABAergic activity in the brain. Evidence for some involvement of GABAergic mechanisms in the control of feeding and drinking responses is reviewed. Only a few data are so far available to link benzodiazepines effects on ingestional behaviour directly to GABAergic transmission. A major current theme in the psychopharmacology of feeding and drinking behaviour is the possible involvement of endogenous opioid peptides. There is a strong suggestion in the experimental data that there are links between benzodiazepine and endorphinergic mechanisms in relation to ingestional responses. A promising future line of approach appears to be a delineation of benzodiazepine-GABA-endorphin interrelations in the control of food and water consumption.