EFFECTS OF PRENATAL DIAZEPAM ON 2-WAY AVOIDANCE-BEHAVIOR, SWIMMING NAVIGATION AND BRAIN LEVELS OF BENZODIAZEPINE LIKE MOLECULES IN MALE ROMAN HIGH-AVOIDANCE AND LOW-AVOIDANCE RATS

Utilizing psychogenetically selected Roman high- and low-avoidance rat s (RHA/Verh and RLA/Verh), the present experiments investigated the ef fects of prenatally administered vehicle and diazepam (1 and 3 mg/kg p er day, SC) on the behavior and neurochemistry of adult, male offsprin g. Active, two-way avoidance behavior was analyzed in 96 rats, at 6 mo nths of age, and swimming navigation in 68 others, at 11 months. Three weeks after testing, selected brain areas from the latter animals wer e immunoassayed for benzodiazepine (BZD)-like molecules. The 3 mg/kg d ose of diazepam both decreased freezing behavior in the shuttle box an d reduced the hippocampal content of BZD-like molecules-in the RLA/Ver h male rats. Swimming navigation (spatial learning), at which the RLA/ Verh rats were more adept, was not specifically affected by prenatal d iazepam in either rat line. The possibility exists that an increased h ippocampal release of BZD-like substances may be necessary to alter sh uttle box behavior in RLA/Verh rats.