Long term neurological and behavioral effects of graded perinatal asphyxiain the rat

Perinatal hypoxic-ischemic states can cause irreversible damage to the brai n, ranging from minimal brain dysfunction to death. Only few studies have b een reported describing neurological, cognitive and behavioral deficits fol lowing perinatal asphyxia. We therefore decided to study long term effects of perinatal asphyxia in a well-documented animal model resembling the clin ical situation. Caeserean section in rats was performed and the pups, still in the uterus horns, were placed into a water bath at 37 degrees C for per iods of 5-20 min; pups were then given to surrogate mothers and examined at three month of age. Examinations consisted of a battery of motor and refle x tests, Morris water maze, multiple T-maze, elevated plus maze and open fi eld studies. No abnormalities were found in rats even with long periods of perinatal asphyxia by neurological examination, in the open field and in ma zes. Interestingly, in the elevated plus maze rats with long lasting exposu re to hypoxia (15 and 20 min of asphyxia) showed reduced anxiety-related be havior. This finding may be relevant for the explanation of anxiety related disorders in adulthood with a tentative history in the perinatal period.