Analysis of stimulant locomotor effects of modafinil in various strains of mice and rats.

Locomotor effects of modafinil were analysed and compared in various strains of mice and rats. A stimulation of locomotor activity was evidenced in all tested strains of mice: Swiss CD1, BALB/c, DBA2, C3H, B6CBAF1/JICO, Nude CD1 and in all tested strains of rats: Long Evans, Sprague Dawley, Wistar. In mice, from 10 mg/kg intraperitoneal, a precocious stimulant effect was observed. The drug seems to operate in its native form on the mouse brain since its intracerebroventricular administration (from 15 micrograms/mouse) elicited a stimulation of locomotion. In rats, the effective doses were higher (from 40 mg/kg ip); the effects of modafinil mainly oppose to the decrease in locomotion (habituation) which normally occurs in control animals. In addition, it was observed that administration of modafinil in rats habituated to their environment induced a recovery of locomotor activity.