Treatment of adolescent rats with 1-benzylpiperazine: a preliminary study of subsequent behavioral effects

Adolescent male and female rats were intraperitoneally injected with either isotonic saline or 10 mg/kg/day 1-benzylpiperazine (BZP) from postnatal days 45 to 55. Approximately 17 days later, assessments were made of their responsiveness to a novel brightness change in a Y-maze, their ambulation, rearing, defecation and social interactions in an open field, and their dark to light emergence latencies and defecation in an emergence apparatus. Compared with saline controls, rats that had been previously treated with BZP entered the novel Y-maze arm less often, spent less time in it and entered both arms less often and spent less time in them, ambulated and reared less in the open field, reared proportionately less often in the center squares and spent less time in social interaction, and, in the emergence apparatus, emerged into the light more slowly and also defecated less often in the darkened start box. Female but not male rats also spent more time restraining their partner rat while socially interacting in the open field. With few exceptions, the results were consistent with BZP treatment during adolescence having led to heightened anxiety possibly because of interference with maturation of anxiety-associated forebrain mechanisms operated by 5-HT.