Hippocampal interleukin-1β gene expression during long-term potentiation decays with age

Abstract

Interleukin-1 is a cytokine that, apart from its contribution to immunoregulation, can affect neuroendocrine mechanisms and brain functions. We have previously shown that an increase in the endogenous production of IL-1 in the dentate gyrus during LTP is relevant for the maintenance of this process. We report here that in middle-aged rats (12 to 16 months old), enhancement of IL-1 gene expression is diminished compared to that in young animals. Furthermore, basal levels of IL-1 gene expression were slightly reduced in middle-aged rats. The reduced upregulation of IL-1 gene expression during LTP was not accompanied by overt impairment of potentiation, suggesting that either the level of the cytokine is still enough to maintain synaptic plasticity in the dentate gyrus or that compensatory, probably less efficient, mechanisms develop during aging.