[The characteristics of the startle reflex to an acoustic stimulus in rats with hereditary stress-sensitive arterial hypertension: the effect of chronic stress in the prepuberty period].

Acoustic startle reflex was studied in young and adult rats with hereditary stress-induced arterial hypertension (HSIAH) in comparison with original normotensive Wistar strain. Immediate and long-lasting effects of chronic handling or chronic unpredictable stress at the age of 4 and 5 weeks on manifestations of the startle reflex were studied. The amplitude of the sensorimotor reaction was lower in both young (38-day-old) and adult (4-month-old) HSIAH rats than in age-matched normotensive Wistar rats. Young and adult hypertensives demonstrated significant inhibition of startle reflex when the startling stimulus was preceded by a weak prepulse. Such prepulse inhibition was not expressed in young or adult Wistar rats. Chronic handling as well as chronic unpredictable stress during the 4th and 5th weeks of life potentiated the startle amplitude in young HSIAH rats. The prepulse inhibition level did not depend on the chronic stress. The long-lasting effect of the prepubertal chronic stress depended on the type of the stress factors.