Play soliciting in juvenile male rats: effects of caffeine, amphetamine and methylphenidate.

Three standard CNS stimulants were tested for effect on juvenile play soliciting in prepubertal male rats (n = 120). Three dosages of each stimulant were compared with a saline control. Soliciting behavior was isolated and magnified by a novel method incorporating pretest social deprivation and social response to a standard nonplayful social stimulus pretreated with scopolamine HBr. Caffeine significantly decreased frequency of play soliciting only at the high dose of 40 mg/kg. Methylphenidate and d-amphetamine significantly decreased play soliciting at all dosages tested. The method is proposed as a generally useful experimental paradigm in analyses of drug effects on play soliciting. Advantages include individual measures of soliciting behavior that correlate reliably with measures of rough-and-tumble play fighting.