GABA A Modulators

The GABA-A receptor is a heteropentameric, ligand-gated chloride channel and the main fast inhibitory receptor of the brain: the GABA binding sites lie at the interfaces between neighbouring alpha and beta subunits, and when GABA activates the receptor chloride flows across the membrane down its electrochemical gradient, decreasing the neuron's ability to generate a new action potential. Drugs in this class act at a separate allosteric site rather than at the GABA site; UniProt records the receptor as allosterically activated by benzodiazepines, by the anaesthetic alphaxalone and by pentobarbital, these being bound at a distinct allosteric effector binding site. Pharmacologically, dependence on endogenous GABA is what separates a modulator from an agonist, but that is not a line the source classification enforces: zolazepam and zolpidem are filed both here and in the agonist class N0000000196, and secobarbital both here and in the GABA-B modulator class N0000000251. What the member list does show plainly is that this class carries most of the injectable and inhalational anaesthetic and sedative agents in veterinary use - desflurane, enflurane, etomidate, isoflurane, methoxyflurane, midazolam, propofol, secobarbital and sevoflurane.