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Sex differences after chronic stress in the expression of opioid-, stress- and neuroplasticity-related genes in the rat hippocampus.

TitleSex differences after chronic stress in the expression of opioid-, stress- and neuroplasticity-related genes in the rat hippocampus.
Publication TypeJournal Article
Year of Publication2018
AuthorsRandesi M, Zhou Y, Mazid S, Odell SC, Gray JD, J da Rosa C, McEwen BS, Milner TA, Kreek MJeanne
JournalNeurobiol Stress
Volume8
Pagination33-41
Date Published2018 Feb
ISSN2352-2895
Abstract

Opioid peptides and their receptors re-organize within hippocampal neurons of female, but not male, rats following chronic immobilization stress (CIS) in a manner that promotes drug-related learning. This study was conducted to determine if there are also sex differences in gene expression in the hippocampus following CIS. Adult female and male rats were subjected to CIS (30 min/day) for 10 days. Twenty-four hours after the last stressor, the rats were euthanized, the brains were harvested and the medial (dentate gyrus/CA1) and lateral (CA2/CA3) dorsal hippocampus were isolated. Following total RNA isolation, cDNA was prepared for gene expression analysis using a RT Profiler PCR expression array. This custom designed qPCR expression array contained genes for opioid peptides and receptors, as well as genes involved in stress-responses and candidate genes involved in synaptic plasticity, including those upregulated following oxycodone self-administration in mice. Few sex differences are seen in hippocampal gene expression in control (unstressed) rats. In response to CIS, gene expression in the hippocampus was altered in males but not females. In males, opioid, stress, plasticity and kinase/signaling genes were all down-regulated following CIS, except for the gene that codes for corticotropin releasing hormone, which was upregulated. Changes in opioid gene expression following chronic stress were limited to the CA2 and CA3 regions (lateral sample). In conclusion, modest sex- and regional-differences are seen in expression of the opioid receptor genes, as well as genes involved in stress and plasticity responses in the hippocampus following CIS.

DOI10.1016/j.ynstr.2018.01.001
Alternate JournalNeurobiol Stress
PubMed ID29888302
PubMed Central IDPMC5991341
Grant ListR01 DA008259 / DA / NIDA NIH HHS / United States