title: Insensitivity to anaesthetic agents conferred by a class of GABA(A) receptor subunit.
abstract: A common feature of general anaesthetic agents is their ability to potentiate neuronal inhibition through GABA(A) (gamma-aminobutyric acid) receptors. At concentrations relevant to clinical anaesthesia, these agents cause a dramatic stimulation of the chloride currents that are evoked by the binding of the natural ligand, GABA. Although there is widespread evidence that the sensitivity of GABA(A) receptors to anaesthetic agents is heterogeneous, the structural basis of these differences is largely unknown. Variations in subunit composition can have profound effects on the sensitivity of GABA(A) receptors to modulatory agents such as benzodiazepines. However, strict subunit specificity has not been demonstrated for the potentiating effects of anaesthetic agents. Here we describe a new class of human GABA(A) receptor subunit (epsilon) that can assemble with alpha- and beta-subunits and confer an insensitivity to the potentiating effects of intravenous anaesthetic agents. The epsilon-subunit also abolishes the normal outward rectification of recombinant receptors in which it assembles. The expression pattern of this subunit in the brain suggests a new target for manipulation of neuronal pathways within the basal ganglia.
authors.affiliation: The Institute for Genomic Research, Rockville, Maryland 20850, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Davies
authors.forename: M C
authors.initials: MC
authors.lastname: Hanna
authors.forename: T G
authors.initials: TG
authors.lastname: Hales
authors.forename: E F
authors.initials: EF
authors.lastname: Kirkness
mesh_terms: D000595:Amino Acid Sequence; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D016384:Consensus Sequence; D018076:DNA, Complementary; D005442:Flumazenil / Q000494:pharmacology; D005445:Flunitrazepam / Q000494:pharmacology; D018682:GABA Agents / Q000494:pharmacology; D006801:Humans; D008969:Molecular Sequence Data; D009118:Muscimol / Q000378:metabolism; D010424:Pentobarbital / Q000494:pharmacology; D010852:Picrotoxin / Q000494:pharmacology; D011280:Pregnanolone / Q000494:pharmacology; D015742:Propofol / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011963:Receptors, GABA-A / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000187:drug effects / Q000235:genetics; D014162:Transfection; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
chemical_list: D018686:Anesthetics, Intravenous; D001640:Bicuculline; D018076:DNA, Complementary; D005442:Flumazenil; D005445:Flunitrazepam; D018682:GABA Agents; D009118:Muscimol; D010424:Pentobarbital; D010852:Picrotoxin; D011280:Pregnanolone; D015742:Propofol; D012333:RNA, Messenger; D011963:Receptors, GABA-A; D011994:Recombinant Proteins; D005680:gamma-Aminobutyric Acid