<prompt> Barbiturates acts on -a - adrenergic receptorsb - adrenergic receptorsCholinergic receptorsGABA receptor  <response>: Ans. is d i.e., GABA receptors o Barbiturates act primarily at the GABA - BZD receptor - Cl- channel complex and potentiate GABAergic inhibition by increasing the lifetime of Cl- channel opening caused by GABA Contrast benzodiazepines which enhance frequency of Cl- channel opening - GABA facilitatory action.o Benzodiazepines antagonist - Flumazenilo Benzodiazepines inverse agonist - b - carboline DMCMDrugs affectign GABA receptorsGABAA receptoro GABA - Endogenous agonisto Muscimol - Agonisto Bicuculline - Competitive antagonistGABAB receptoro Baclofen - Agonisto Saclofen - Antagonisto Picrotoxin - Blocks Cl- channel noncompetitivelyo Barbiturate - Agonist at aliostearic site other than BZD siteo Benzodiazepine - Agonist at aliostearic site BZD siteo b-earboline DMCM - Inverse agonist at BZD siteo Flumazenil - Competitive antagonist at BZD siteo Alcohal, inhalation anaesthetic, propofol - open Cl- channel directly,o Alphaxoloneo Zopiclone, zolpidem, zoleplon - agonist at BZD site,o Anticonvulsants Gabapentine, vigabaterineo Ivermectin 