<prompt> Benzodiazepine acts through which receptor:ChlorideGABANMDAb adrenergic  <response>: Ans: b GABA Ref: KDT, 6th ed, p. 395BZDs act by enhancing presynapticpostsynaptic inhibition through a BZD receptor which is an integral part of the GABAA receptor-Cl- channel complex.They have GABA facilitatory action and no GABA mimetic action i.e. the BZDs increase the frequency of Cl channel opening induced by sub maximal concentrations of GABA and enhance GABA binding to GABAA receptor but they do not themselves increase Cl- conductance.Flumazenil is a competitive antagonist at BZD siteCarboline b - is an inverse agonist at BZD siteBicuculline - Competitive antagonist at GABAA receptorMuscimol - acts as agonist at GABAA site.Drugs active at the benzodiazepine receptor may be divided into four categories based on their elimination half-lives:1 Ultra short acting: Midazolam2 Short acting t2 6 hours: Triazolam, the nonbenzodiazepine zolpidem t12 2 hours and zopiclone t12 5-6 hours.3 Intermediate-acting t12 6-24 hours: Estazolam and temazepam.4 long-acting t12 24 hours:Flurazepam, diazepam, and quazepam.Flurazepam has the longest half life of 50-100 hrs. 