Chewing during chronic stress ameliorates stress-induced suppression of neurogenesis in the hippocampal dentate gyrus in aged SAMP8 mice

Abstract

Chronic stress suppresses neurogenesis in the hippocampal dentate gyrus (DG). Chewing under chronic stress is reported to suppress stress-induced responses. We examined whether chewing under restraint stress prevents restraint stress-induced suppression of neurogenesis in the hippocampal DG in aged senescence-accelerated prone (SAMP8) mice. Restraint stress increased plasma corticosterone levels, and suppressed cell proliferation, survival, and differentiation of newborn cells in the hippocampal DG. In contrast, chewing under restraint stress prevented the increase in plasma corticosterone levels, and ameliorated the suppression of cell proliferation, survival, and differentiation of newborn cells in the hippocampal DG. These results suggest that chewing under restraint stress prevents the stress-induced increase in plasma corticosterone levels, leading to the inhibition of stress-induced suppression of neurogenesis in the hippocampal dentate gyrus.