New Context Significantly Changes Expression of Irs2 Gene in Hippocampal Areas

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Anastasia M. Shvadchenko¹, Maria N. Volobueva¹, Violetta O. Ivanova¹, Alexandr P. Beletskiy¹, Gulnur R. Smirnova¹, Natalia V. Bal¹, and Pavel M. Balaban^1,a*

¹Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 117485 Moscow, Russia

^* To whom correspondence should be addressed.

Received May 20, 2022; Revised September 9, 2022; Accepted September 19, 2022

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Memory formation is a complex process involving changes in the synaptic activity and gene expression encoding the insulin-like growth factors. We analyzed changes in the expression of genes encoding the insulin/insulin-like growth factors’ proteins at the early period of learning in the CA1 region and dentate gyrus of the dorsal and ventral hippocampus in mice 1 hour after presentation of a new context (contextual fear conditioning) with and without negative reinforcement. It was found that in addition to changes in the expression of immediate early genes c-Fos (in all studied hippocampal fields) and Arc (in dorsal and ventral CA1, as well as in dorsal dentate gyrus), exposure to a new context significantly altered expression of the insulin receptor substrate 2 gene (Irs2) in dorsal CA1 and ventral dentate gyrus irrespectively of the negative reinforcement, which suggests participation of the insulin/IGF system in the early stages of neural activation during learning.

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KEY WORDS: learning, memory, Irs2, hippocampus, transcriptome, fear conditioning

DOI: 10.1134/S0006297922110037

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