Effect of neonatal handling in rats with hereditary stress-induced arterial hypertension (NISAG rats).

NISAG rats were subjected to handling on days 1-21 after birth. Blood pressure and plasma corticosterone concentration were measured in 6-month-old handled and control NISAG rats at rest and under stress conditions. Animal behavior was studied in the open-field test. Handling had no effect on body weight and relative weights of the heart and adrenal glands. In rats subjected to handling, changes in blood pressure and adrenal cortex produced by acute emotional stress (30-min restriction) were less pronounced than in control animals. Handled rats demonstrated less fear in a new environment and exhibited high exploratory activity in the open-field test. Our findings suggest that neonatal handling reduces stress reactivity and decreases the severity of hypertension in adult NISAG rats.