Fig. 1. Circadian rhythms in 8-OH-DPAT–induced forepaw treading and head weaving (5-HT syndrome), observed in five experiments performed at 3-month intervals. Values are the mean ± SD of eight animals. The black bar corresponds to the dark period. *p < .05, **p < .01, ***p < .001, ****p < .0001 (analysis of variance). Reproduced with permission from Springer-Verlag, from Nagayama H, Lu J-Q. Circadian and circannual rhythms in the function of central 5-HT1A receptors in laboratory rats. Psychopharmacology 1998;135:279–83.
