Figure 3.

Nicotine-induced CYP2B reduces propofol-induced sleep time, with no effect of nicotinic acetylcholine receptors (nAChR) blockade on this response. (a) Seven-day nicotine treatment significantly reduced mean sleep time by 60% compared with the animals' sleep time at baseline (n=52, ^*P<0.0001). Diamonds represent mean sleep time±standard deviation. (b) An intracerebroventricular (i.c.v.) injection of C8-xanthate (C8-X) reversed the reduction in sleep time owing to nicotine treatment and sleep time was extended beyond the baseline sleep times (P=0.02; n=4). (c) Pretreatments with the nAChR blocker chlorisondamine and (d) the nAChR antagonist mecamylamine did not alter propofol sleep at baseline or the reduction in sleep time following nicotine treatment, and i.c.v. C8-X reversed the reduction in both groups (↔P<0.05; n=6/group).