Effect of sex and castration on nicotine-induced activity responses

The nature of the short-term interactions between nicotine and sex hormones in affecting activity remain unclear. The present study was an investigation of these effects. Three levels of nicotine injection--0.0 (saline control), 0.2 mg/kg body weight, and 0.4 mg/kg body weight-were given to male, female, and castrated Sprague-Dawley albino rats. Activity was measured when the animals were 6 weeks and 12 weeks old. Nicotine produced an initial depression of activity relative to the saline control levels, and a later activation which peaked at 40 to 60 minutes. The biphasic effect was most striking in female animals, but the forms of the curves relating activity to time in all groups were quite similar.