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Anonymous
>>411013 >Benzodiazepines produce a range of effects from depressing to stimulating the central nervous system via modulating the GABAA receptor, the most prevalent inhibitory receptor within the brain. The subset of GABAA receptors that also bind benzodiazepines are referred to as benzodiazepine receptors (BzR). The GABAA receptor is composed of five subunits, most commonly two ?'s, two ?'s, and one ? (?2?2?). For each subunit, multiple subtypes exist (?1-6, ?1-3, and ?1-3). GABAA receptors that are made up of different combinations of subunit subtypes have different properties, different distributions within the brain, and different activities relative to pharmacological and clinical effects.
>Benzodiazepines bind at the interface of the ? and ? subunits on the GABAA receptor. Benzodiazepine binding also requires that alpha subunits contain a histidine amino acid residue, (i.e., ?1, ?2, ?3 and ?5 containing GABAA receptors). For this reason, benzodiazepines show no affinity for GABAA receptors containing ?4 and ?6 subunits, which contain an arginine instead of a histidine residue. Other sites on the GABAA receptor also bind neurosteroids, barbiturates and certain anesthetics.[12]
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