@article {Borghese208, author = {C. M. Borghese and D. F. Werner and N. Topf and N. V. Baron and L. A. Henderson and S. L. Boehm II and Y. A. Blednov and A. Saad and S. Dai and R. A. Pearce and R. A. Harris and G. E. Homanics and N. L. Harrison}, title = {An Isoflurane- and Alcohol-Insensitive Mutant GABAA Receptor α1 Subunit with Near-Normal Apparent Affinity for GABA: Characterization in Heterologous Systems and Production of Knockin Mice}, volume = {319}, number = {1}, pages = {208--218}, year = {2006}, doi = {10.1124/jpet.106.104406}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {Volatile anesthetics and alcohols enhance transmission mediated by γ-aminobutyric acid type A receptors (GABAARs) in the central nervous system, an effect that may underlie some of the behavioral actions of these agents. Substituting a critical serine residue within the GABAAR α1 subunit at position 270 with the larger residue histidine eliminated receptor modulation by isoflurane, but it also affected receptor gating (increased GABA sensitivity). To correct the shift in GABA sensitivity of this mutant, we mutated a second residue, leucine at position 277 to alanine. The double mutant α1(S270H,L277A)β2γ2S GABAAR was expressed in Xenopus laevis oocytes and human embryonic kidney (HEK)293 cells, and it had near-normal GABA sensitivity. However, rapid application of a brief GABA pulse to receptors expressed in HEK293 cells revealed that the deactivation was faster in double mutant than in wild-type receptors. In all heterologous systems, the enhancing effect of isoflurane and ethanol was greatly decreased in the double mutant receptor. Homozygous knockin mice harboring the double mutation were viable and presented no overt abnormality, except hyperactivity. This knockin mouse line should be useful in determining which behavioral actions of volatile anesthetics and ethanol are mediated by the GABAARs containing the α1 subunit. The American Society for Pharmacology and Experimental Therapeutics}, issn = {0022-3565}, URL = {https://jpet.aspetjournals.org/content/319/1/208}, eprint = {https://jpet.aspetjournals.org/content/319/1/208.full.pdf}, journal = {Journal of Pharmacology and Experimental Therapeutics} }