A gain-of-function mutation in the GABA receptor produces synaptic and behavioral abnormalities in the mouse.

TitleA gain-of-function mutation in the GABA receptor produces synaptic and behavioral abnormalities in the mouse.
Publication TypeJournal Article
Year of Publication2005
AuthorsHomanics GE, Elsen FP, Ying S-W, Jenkins A, Ferguson C, Sloat B, Yuditskaya S, Goldstein PA, Kralic JE, Morrow AL, Harrison NL
JournalGenes Brain Behav
Date Published2005 Feb
KeywordsAmino Acid Substitution, Animals, Behavior, Animal, Behavioral Symptoms, Brain, Chimera, Female, Gene Targeting, Male, Maternal Behavior, Mice, Mice, Inbred C57BL, Mice, Mutant Strains, Mice, Transgenic, Motor Activity, Motor Skills, Mutagenesis, Site-Directed, Neural Inhibition, Phenotype, Receptors, GABA-A, RNA, Messenger, Rotarod Performance Test, Synaptic Transmission

In mammalian species, inhibition in the brain is mediated predominantly by the activation of GABAA receptors. We report here changes in inhibitory synaptic function and behavior in a mouse line harboring a gain-of-function mutation at Serine 270 (S270) in the GABAA receptor alpha1 subunit. In recombinant alpha1beta2gamma2 receptors, replacement of S270 by Histidine (H) results in an increase in sensitivity to gamma-aminobutyric acid (GABA), and slowing of deactivation following transient activation by saturating concentrations of GABA. Heterozygous mice expressing the S270H mutation are hyper-responsive to human contact, exhibit intention tremor, smaller body size and reduced viability. These mice also displayed reduced motor coordination, were hypoactive in the home cage, but paradoxically were hyperactive in a novel open field environment. Heterozygous knockin mice of both sexes were fertile but females failed to care for offspring. This deficit in maternal behavior prevented production of homozygous animals. Recordings from brain slices prepared from these animals revealed a substantial prolongation of miniature inhibitory postsynaptic currents (IPSCs) and a loss of sensitivity to the anesthetic isoflurane, in neurons that express a substantial amount of the alpha1 subunit. The results suggest that the biophysical properties of GABAA receptors are important in determining the time-course of inhibition in vivo, and suggest that the duration of synaptic inhibition is a critical determinant that influences a variety of behaviors in the mouse.

Alternate JournalGenes Brain Behav.
PubMed ID15660664
Grant ListAA090013 / AA / NIAAA NIH HHS / United States
AA10422 / AA / NIAAA NIH HHS / United States
GM 45129 / GM / NIGMS NIH HHS / United States
GM 66840 / GM / NIGMS NIH HHS / United States
GM47818 / GM / NIGMS NIH HHS / United States