Electrophysiological and behavioral responses to ketamine in mice with reduced Akt1 expression
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A number of studies have associated reduced Akt1 expression with vulnerability for schizophrenia. Although mice with deletion of a single copy of the Akt1 gene (Akt1+/−) show reduced Akt1 expression relative to wild-type (WT) animals, the extent to which these mice show schizophrenia-like phenotypic changes and/or increased susceptibility to epigenetic or non-genetic factors related to schizophrenia is unknown.
Mutant mice were assessed on electroencephalographic/event-related potential (EEG/ERP) and behavioral (acoustic startle and pre-pulse inhibition) measures relevant to schizophrenia. Mice were also assessed following exposure to the NMDA receptor antagonist ketamine, a potent psychotomimetic drug, in order to assess the role of reduced Akt1 expression as a vulnerability factor for schizophrenia. Methods Akt1+/−, Akt1−/−, and WT mice received a series of paired-click, white noise stimuli, following ketamine (50 mg/kg) and saline injections. EEG was analyzed for ERPs and event-related power. Akt1+/− and WT mice were also assessed on PPI following ketamine (50 mg/kg) or saline injection.
Akt1+/− and Akt1−/− mice displayed reduced amplitude of the P20 component of the ERP to the first click of a paired-click stimulus, as well as reduced S1–S2 difference for P20 and N40 components, following ketamine. Mutant mice also showed increased reduction in gamma synchrony and theta suppression following ketamine. Akt1+/− mice displayed reduced pre-pulse inhibition.
Reduced genetic expression of Akt1 facilitated ketamine-induced changes of EEG and behavior in mice, suggesting that reduced Akt1 expression can serve as a vulnerability factor for schizophrenia.
KeywordsSchizophrenia ERSP ITC P50 N100 Evoked-potential Gamma Theta Ketamine Drug abuse
- Blasi G, Napolitano F, Ursini G, Taurisano P, Romano R, Caforio G, Fazio L, Gelao B, Di Giorgio A, Iacovelli L, Sinibaldi L, Popolizio T, Usiello A, Bertolino A (2012) DRD2/AKT1 interaction on D2 c-AMP independent signaling, attentional processing, and response to olanzapine treatment in schizophrenia. Proc Natl Acad Sci U S A 108:1158–1163CrossRefGoogle Scholar
- Cao YA, Featherstone RE, Gandal MJ, Liang Y, Jutzeler C, Saunders J, Tatard-Leitman V, Chen J, Weinberger DR, Lerman C, Siegel SJ (2012) Nicotine normalizes event related potentials in COMT-Val-tg mice and increases gamma and theta spectral density. Behav Neurosci 126:332–343CrossRefPubMedGoogle Scholar
- Carlen M, Meletis K, Siegle JH, Cardin JA, Futai K, Vierling-Claassen D, Ruhlmann C, Jones SR, Deisseroth K, Sheng M, Moore CI, Tsai LH (2011) A critical role for NMDA receptors in parvalbumin interneurons for gamma rhythm induction and behavior. Mol Psychiatry 17:537–548CrossRefPubMedGoogle Scholar
- Di Forti M, Iyegbe C, Sallis H, Kolliakou A, Falcone MA, Paparelli A, Sirianni M, La Cascia C, Stilo SA, Marques TR, Handley R, Mondelli V, Dazzan P, Pariante C, David AS, Morgan C, Powell J, Murray RM (2012) Confirmation that the AKT1 (rs2494732) genotype influences the risk of psychosis in cannabis users. Biol Psychiatry 72:811–816CrossRefPubMedGoogle Scholar
- Ehrlichman RS, Gandal MJ, Maxwell CR, Lazarewicz MT, Finkel LH, Contreras D, Turetsky BI, Siegel SJ (2009) N-methyl-d-aspartic acid receptor antagonist-induced frequency oscillations in mice recreate pattern of electrophysiological deficits in schizophrenia. Neuroscience 158:705–712CrossRefPubMedGoogle Scholar
- Krystal JH, Karper LP, Seibyl JP, Freeman GK, Delaney R, Bremner JD, Heninger GR, Bowers MB Jr, Charney DS (1994) Subanesthetic effects of the noncompetitive NMDA antagonist, ketamine, in humans. Psychotomimetic, perceptual, cognitive, and neuroendocrine responses. Arch Gen Psychiatry 51:199–214CrossRefPubMedGoogle Scholar
- Ohi K, Hashimoto R, Yasuda Y, Fukumoto M, Nemoto K, Ohnishi T, Yamamori H, Takahashi H, Iike N, Kamino K, Yoshida T, Azechi M, Ikezawa K, Tanimukai H, Tagami S, Morihara T, Okochi M, Tanaka T, Kudo T, Iwase M, Kazui H, Takeda M (2011) The AKT1 gene is associated with attention and brain morphology in schizophrenia. World J Biol Psychiatry. doi:10.3109/15622975.2011.591826
- Tan HY, Nicodemus KK, Chen Q, Li Z, Brooke JK, Honea R, Kolachana BS, Straub RE, Meyer-Lindenberg A, Sei Y, Mattay VS, Callicott JH, Weinberger DR (2008) Genetic variation in AKT1 is linked to dopamine-associated prefrontal cortical structure and function in humans. J Clin Invest 118:2200–2208PubMedGoogle Scholar