Dose–response effects of SB-215505 (0.1, 0.3 and 1.0 mg kg−1 i.p.) on motor activity (a) and different vigilance states in conscious, freely moving rats in the first hour after treatment. W (b), SWS-1 (c), SWS-2 (d), IS (e) and PS (f). All columns represent mean values (±s.e.m., n=6). *Significant effect of SB-215505 compared to vehicle, P<0.05.