Figure 5

Comparison of the relative timing of 5-HT onset (5HT-on) and melatonin onset (MT-on). SD: red dots (n = 6), PVG: blue dots (n = 4), LEW: yellow dots (n = 4), Wistar: green dots (n = 8), Syrian hamsters: blue dots (n = 3). The 5HT-on represents the intervals (min) between the dark onset (18:00 h in all animals) and the early 5-HT surge at 80% of the nocturnal maximum levels. The MT-on indicates the time interval (min) between the dark onset (18:00 h) and the melatonin onset at 20% of the nocturnal maximum levels. The vertical dashed line represents the 5HT-on at 60 min, whereas the horizontal dashed lines represent values of MT-on from hamsters (upper line, 300 min) and rats (lower line, 110 min) when 5HT-on is 60 min.