| First Author | Abdulzahir A | Year | 2023 |
| Journal | Int J Mol Sci | Volume | 24 |
| Issue | 6 | PubMed ID | 36982709 |
| Mgi Jnum | J:355422 | Mgi Id | MGI:7450206 |
| Doi | 10.3390/ijms24065637 | Citation | Abdulzahir A, et al. (2023) Changes in Memory, Sedation, and Receptor Kinetics Imparted by the beta2-N265M and beta3-N265M GABA(A) Receptor Point Mutations. Int J Mol Sci 24(6) |
| abstractText | Point mutations in the beta2 (N265S) and beta3 (N265M) subunits of gamma-amino butyric acid type A receptors (GABA(A)Rs) that render them insensitive to the general anesthetics etomidate and propofol have been used to link modulation of beta2-GABA(A)Rs to sedation and beta3-GABA(A)Rs to surgical immobility. These mutations also alter GABA sensitivity, and mice carrying the beta3-N265M mutation have been reported to have impaired baseline memory. Here, we tested the effects of the beta2-N265M and beta3-N265M mutations on memory, movement, hotplate sensitivity, anxiety, etomidate-induced sedation, and intrinsic kinetics. We found that both beta2-N265M and beta3-N265M mice exhibited baseline deficits in the Context Preexposure Facilitation Effect learning paradigm. Exploratory activity was slightly greater in beta2-N265M mice, but there were no changes in either genotype in anxiety or hotplate sensitivity. beta2-N265M mice were highly resistant to etomidate-induced sedation, and heterozygous mice were partially resistant. In rapid solution exchange experiments, both mutations accelerated deactivation two- to three-fold compared to wild type receptors and prevented modulation by etomidate. This degree of change in the receptor deactivation rate is comparable to that produced by an amnestic dose of etomidate but in the opposite direction, indicating that intrinsic characteristics of GABA(A)Rs are optimally tuned under baseline conditions to support mnemonic function. |
