Chronobiotic effect of melatonin following phase shift of light/dark cycles in the field mouse Mus booduga

Abstract

The objective of this study was to assess whether melatonin accelerates the reentrainment of locomotor activity after 6 h of advance and delay phase shifts following exposure to LD 12:12 cycle (simulating jet-lag/shift work). An experimental group of adult male held mice Mus booduga were subjected to melatonin (1 mg/kg) through i.p. and the control group were treated with 50% DMSO. The injections were administered an three consecutive days following 6 h of phase advance and delay, at the expected time of ''lights off''. The results show that melatonin accelerates the re-entrainment after phase advance (29%) when compared with control mice, In the 6 h phase delay study, the experimental mice (melatonin administered) take more cycles for re-entrainment (51%) than the control. Further, the results suggest that though melatonin may be useful for the treatment of jet-lag caused by eastward flight (phase advance) it may not be useful for westward flight (phase delay) jet-lag.