Chronic stress during prepubertal development: immediate and long-lasting effects on arterial blood pressure and anxiety-related behavior.

The present work was undertaken to study the immediate and long-lasting effects of environmental stress during prepubertal life in rats with inherited stress-induced arterial hypertension (ISIAH) and normotensive Wistar rats on blood pressure (BP) levels and anxiety-related behavior. Two models of chronic stress (21-32 postnatal days) were used: repeated handling (HS) and unpredictable stress (US) of daily exposures to a variety of mild physical or psychoemotional stressors. Rats were tested just after the end of the chronic stress period and then at the age of 4 months. Chronic prepubertal stress did not affect the basal or stress-induced BP levels in young or adult Wistar rats. In ISIAH rats, chronic stress during the early phase of hypertension development did not accelerate its formation and did not augment its manifestation in adults. Moreover, the basal BP was decreased in young and adult ISIAH rats exposed to HS or US as compared to the age-matched controls. No long-lasting effect on BP elevation under acute stress in adults was found. Plasma corticosterone levels at resting and acute stress conditions were not changed in adult rats that had experienced prepubertal stress. Hypertensive rats proved to be less anxious in the elevated plus-maze test. The immediate effects of chronic stress were similar in the two rat strains: HS had an anxiolytic action while US stimulated anxiety. Long-lasting consequences depended on the rat strain: the anxiolytic effect of HS was retained in Wistar rats and US caused a greater anxiety in adult ISIAH rats. The data do not evidence that symptoms of anxiety are related to the development and maintenance of stress-sensitive arterial hypertension in ISIAH rats.