Figure 4
From: Relationship between nocturnal serotonin surge and melatonin onset in rodent pineal gland
Circadian profiles of pineal 5-HT and melatonin secretion from multiple outbred Syrian hamsters. A. Entrained profiles of 5-HT (upper panel) and melatonin (lower panel) secretion from 3 Syrian hamsters. All data points were normalized to the nocturnal peak values of each circadian cycle. Each hamster is represented by a different color. 5-HT and melatonin secretion from the same hamster is shown in the same color. B. Comparison of 5-HT (upper panel) and melatonin (lower panel) secretion profiles from outbred animals. Data from SD rats (red), Wistar rats (green), and hamsters (blue) are superimposed to show the relative timing of 5-HT and melatonin secretion.