| First Author | Benloucif S | Year | 1996 |
| Journal | J Biol Rhythms | Volume | 11 |
| Issue | 2 | Pages | 113-25 |
| PubMed ID | 8744239 | Mgi Jnum | J:33996 |
| Mgi Id | MGI:81476 | Doi | 10.1177/074873049601100204 |
| Citation | Benloucif S, et al. (1996) Melatonin and light induce phase shifts of circadian activity rhythms in the C3H/HeN mouse. J Biol Rhythms 11(2):113-25 |
| abstractText | This study examines the effect of light pulses and administration of the pineal hormone melatonin on the circadian activity rhythm of C3H/HeN mice. Mice were housed in constant dark in cages equipped with running wheels. Phase shifts in the circadian rhythm of wheel-running activity were measured following treatment with a 15-min pulse of light (300 lux) or administration of vehicle (ethanol/saline) or melatonin (90 micrograms, sc). Light treatment induced phase changes in circadian activity rhythms; specifically, delays during early subjective night (circadian time [CT] 12.5 to CT 18.5) and advances during late subjective night (CT 0.5). A single dose of melatonin administered at various CTs had no consistent effect on free-running circadian activity rhythms. By contrast, melatonin administration for 3 consecutive days at the same clock time induced advances in circadian activity rhythms by more than 1 h when the first dose was administered at CT 10 and induced delays in circadian activity rhythms by up to 1 h when the first dose was administered between CT 24 and CT 2. With the caveat that multi- ple melatonin treatments are required to induce phase shifts, the results suggest that the circadian timing system controlling the rhythm of wheel-running activity in the C3H/HeN mouse is responsive to both light and melatonin. |
