N. Marumoto et al., MELATONIN ACCELERATES REENTRAINMENT OF CIRCADIAN LOCOMOTOR-ACTIVITY RHYTHMS TO NEW LIGHT-DARK CYCLES IN THE RAT, Japanese Journal of Physiology, 46(4), 1996, pp. 347-351
We examined whether continuous melatonin administration through subcut
aneously implanted silastic tubing accelerates reentrainment of circad
ian rhythms of locomotor activity to shifted illumination cycles. We f
ound that rats required less time to reentrain to an advanced or delay
ed phase shift of a light-dark cycle while carrying a silastic implant
filled with melatonin than while carrying an empty implant. These res
ults suggest that continuous administration of melatonin accelerates t
he reentrainment of the circadian locomotor activity rhythm to a new l
ight-dark cycle.