The effects of nalmefene on motor activity and strength/motor coordination. Nalmefene was injected s.c. or administered p.o. (20 and 90 min, respectively, according to its peak plasma concentration) before each test. Motor activity (A, C), mean ± SEM of the accumulated beam breaks for the 30 min following nalmefene administration (A, n = 10 per group; C, n = 11, 10, 10, 10 per group). Rod suspension (B, D), mean ± SEM of the latency to fall in seconds (B, n = 10 per group; D, n = 11, 11, 10, 10 per group) There were no significant differences in motor activity or strength/motor coordination.