Receptor Pharmacology of GABA: A Review

In the present review we have tried to explain the details of GABA and benzodiazepine receptors and also focused on the recent trends of GABA receptors. GABA (gamma amino butyric acid) is mainly synthesized from glutamate and it is a inhibitory neurotransmitters and is classified in to two major types i.e. GABAA and GABAB and recently found GABAc which is also very important and it is functionally similar to that of GABAA. Different drugs acting on GABA receptor are muscimol (direct agonist); bicuculine (direct antagonist), benzodiazepine (indirect agonist), barbiturate (indirect agonist), steroid (indirect agonist), picrotoxin (inverse agonist), Zn, strychnine etc. These drugs are mainly useful in sedative and hypnotic, anterograde amnesia, muscle relaxant, insomnia etc. However, the exact subunit composition of even a single GABAA receptor subtype has not yet been identified. Many more experiments have to be performed in order to reach this goal. If a receptor composition existing in the brain had been identified, a recombinant receptor with the same composition could be expressed in a cell culture system. Thus, the investigation of the various GABAA receptor subtypes and their composition, regional distribution in the brain and pharmacology is not only of tremendous importance for the basic neurosciences but will also result in the rapid development of new and more selective compounds for psychiatry.