The Capability to Learn and Expression of the Insulin-Like Growth Factor II Gene in the Brain of Male Rats Whose Fathers Were Subjected to Stress Factors in the “Stress–Restress” Paradigm

Abstract—We studied the capability to learn in a passive avoidance task and the rate of its extinction in male rats whose fathers were subjected to stress during the period of spermatogenesis using the “stress–restress” paradigm (a model of post-traumatic stress disorder). In the brain of trained and untrained rats, we studied the expression of genes encoding insulin-like growth factor II and H19, the expression of which is imprinted at the early stages of ontogeny. Experimental males exhibited impaired memory consolidation and accelerated extinction of a passive avoidance response. The expression of Igf2 was decreased in the hippocampus and neocortex of untrained male offspring of stressed fathers. The increased expression of the Igf2 and H19 genes was revealed in the hippocampus of male offspring of control fathers 20 h after training, whereas in the experimental rats, the expression of these genes did not alter. Our data show that the impairment of memory in male offspring of stressed fathers may be mediated by decreased expression of the Igf2 gene.