Nicotine-produced antinociception in minimally deprived smokers and ex-smokers.

The antinociceptive effects of two different modes of nicotine administration were investigated using a within-subject design. Ten minimally-deprived, habitual smokers and fifteen ex-smokers were studied in separate experiments. Nicotine was delivered in research cigarettes and tobacco snuff. Pain was induced using the cold pressor test. Subjects in both experiments exhibited pain reduction after nicotine administration without changes in nicotine withdrawal. The results suggest that nicotine can produce physiological and psychological changes that are relevant to the reinforcement of smoking but are independent of the state of nicotine withdrawal.