NICOTINE DISCRIMINATION IN MALE AND FEMALE SMOKERS

Discriminative stimulus effects of nicotine were evaluated in humans u sing formal behavioral drug discrimination procedures. Male and female smokers (n=9 each) were trained on day 1 to reliably discriminate O v ersus 12 mu g/kg nicotine administered by measured-dose nasal spray. A ll subjects were able to reach criterion performance (at least 80% cor rect). Generalization of responding across nicotine doses of 0, 2, 4, 8, and 12 mu g/kg (approximately 0-0.8 mg for typical subject) was the n examined on day 2. Nicotine-appropriate responding was linearly rela ted to dose, and subjects were able to distinguish the smallest dose ( 2 mu g/kg) from placebo. Although there were no differences between ma les and females in behavioral discrimination, subjective effects were correlated with nicotine discrimination in females but not in males. T hese findings indicate that humans are able to discriminate among low doses of nicotine per se, that males and females may differ in the sti muli used to discriminate nicotine, and that drug discrimination proce dures may be more sensitive than traditional subjective effects measur es in distinguishing among low doses of nicotine.