1. A schizophrenia-related sensorimotor deficit links [alpha]3-containing [GABA.sub.A] receptors to a dopamine hyperfunction
- Author
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Yee, B.K., Keist, R., von Boehmer, L., Studer, R., Benke, D., Hagenbuch, N., Dong, Y., Malenka, R.C., Fritschy, J.-M., Bluethmann, H., Feldon, J., Mohler, H., and Rudolph, U.
- Subjects
Schizophrenia -- Genetic aspects ,Sensorimotor integration -- Analysis ,Science and technology - Abstract
Overactivity of the dopaminergic system in the brain is considered to be a contributing factor to the development and symptomatology of schizophrenia. Therefore, the GABAergic control of dopamine functions was assessed by disrupting the gene encoding the [alpha]3 subunit of the GAB[A.sub.A] receptor. [alpha]3 knockout ([alpha]3KO) mice exhibited neither an obvious developmental defect nor apparent morphological brain abnormalities, and there was no evidence for compensatory up-regulation of other major GAB[A.sub.A]-receptor subunits. Anxiety-related behavior in the elevated-plus-maze test was undisturbed, and the anxiolytic-like effect of diazepam, which is mediated by [alpha]2-containing GAB[A.sub.A] receptors, was preserved. As a result of the loss of [alpha]3 GAB[A.sub.A] receptors, the GABA-induced whole-cell current recorded from midbrain dopamine neurons was significantly reduced. Spontaneous locomotor activity was slightly elevated in [alpha]3KO mice. Most notably, prepulse inhibition of the acoustic startle reflex was markedly attenuated in the [alpha]3KO mice, pointing to a deficit in sensorimotor information processing. This deficit was completely normalized by treatment with the antipsychotic D2-receptor antagonist haloperidol. The amphetamine-induced hyperlocomotion was not altered in [alpha]3KO mice compared with WT mice. These results suggest that the absence of [alpha]3-subunit-containing GAB[A.sub.A] receptors induces a hyperdopaminergic phenotype, including a severe deficit in sensorimotor gating, a common feature among psychiatric conditions, including schizophrenia. Hence, agonists acting at [alpha]3-containing GAB[A.sub.A] receptors may constitute an avenue for an effective treatment of sensorimotor-gating deficits in various psychiatric conditions. haloperidol | sensorimotor gating
- Published
- 2005