Changes in the Nature of Behavior and the Activity of the Hypophyseal-Adrenocortical System in the Offspring of Paternal Rats Subjected to Stress in the Stress–Restress Paradigm before Mating

We report here studies of the effects of stressing male rats in the stress–restress paradigm, which is a model of post-traumatic stress disorder (PTSD), on the behavioral phenotype and the hypophyseal-adrenocortical system (HAS) in their adult offspring of both sexes. These experiments showed that only some proportion of males formed a PTSD-like state characterized by a reduced basal corticosterone level. The offspring of these rats had low body weight in the neonatal period of development and as adults were characterized by reduced movement activity and increased behavioral depressivity. Basal and stressed HAS activity in these animals was reduced and the sensitivity of this hormonal axis to negative feedback signals was increased. Behavioral changes were most marked in male offspring, while sequelae of the paternal PTSD-like state in female offspring were seen only in relation to activity levels and HAS activity. The offspring of males not forming a PTSD-like state displayed the smallest changes in behavior and HAS activity. It is suggested that the severity of the action of paternal stress on the offspring is determined by the individual stress resistance of fathers.