BENZODIAZEPINE RECEPTOR ANTAGONISTS - POSSIBLE USES IN THE TREATMENT OF NEUROPSYCHIATRIC DISORDERS

The receptor to which benzodiazepine hypnosedatives and anticonvulsant s bind was discovered and characterised in the late 1970s, Agonists an d inverse agonists that act at various sites within the receptor compl ex have been identified, In addition, antagonists of the benzodiazepin e receptor have been synthesised, At present, flumazenil is the only a gent of this class that is available clinically, Flumazenil has well d ocumented benefits in the treatment of hepatic encephalopathy and benz odiazepine overdose, The drug has also been studied as a potential tre atment for neuropsychiatric illnesses in which dysfunction of the gamm a-aminobutyric acid (GABA)ergic system is implicated as a causal facto r, Potential therapeutic benefits are suggested in benzodiazepine tole rance and withdrawal. benzodiazepine-related amnesia, epilepsy, sleep disorders, cognitive disorders and idiopathic recurrent stupor. In con trast, no clear benefits have been found in alcoholism, anxiety and mo vement disorders. Flumazenil induces few adverse effects, and so repre sents a promising tool for pharmacological investigations of the GABAe rgic system and for imaging of the benzodiazepine receptor. As an imag ing agent it has been used for quantification of the receptor, and as a neuronal marker in epilepsy and cerebral ischaemia.