SEX-DIFFERENCES IN COCAINE-INDUCED AND NICOTINE-INDUCED ANTINOCICEPTION IN THE RAT

Several recent reports describe sex differences in opioid antinocicept ion. The present study examined sex differences in stimulant-induced a ntinociception. On the 50 degrees C hotplate test, cocaine (0.1-1.0 mu g i.c.v.) produced dose- and time-dependent increases in response lat ency in male but not female Sprague-Dawley rats. In contrast, nicotine (3-30 mu g i.c.v.) produced increases in hotplate latency in both sex es, but produced greater effects in females; nicotine also decreased s pontaneous locomotor activity significantly more in females than in ma les. These sex differences probably are not due to differential pharma cokinetics, and underscore the importance of including female subjects in experimental drug research. (C) 1998 Elsevier Science B.V. All rig hts reserved.