The effects of pinealectomy and melatonin implants on circadian locomotor activity responses of the mongolian gerbils exposed to rapid photoperiodic transitions [Hi{dotless}zli{dotless} fotoperiyodik deģisimlere maruz bi{dotless}raki{dotless}lan mogolistan gerbil'lerinde sirkadiyen lokomotor aktivite cevaplari{dotless} üzerine pinealektomi ve melatonin i̇mplantlari{dotless}ni{dotless}n etkileri]

The jet-lag syndrome and the shift-work malaise take place by rapid changes in photoperiod and disturb people's life frequently. in the present study; we wanted to simulate these conditions. control,pinealectomized and melatonin including silastic tube implanted mongolian gerbils were respectively exposed into long (14l:10d),short (8l:16d),constant darkness (0l:24d) and constant light (24l:0d) photoperiods in order to investigate the effects of photoperiod,pineal gland and melatonin hormone in the photoperiodic reentrainment of this species. gerbils showed an light/dark cycle entrained locomotor activity rhythm in long and short photoperiods,free-running in constant darkness and arrhythmic locomotor activity in constant light. the period lengths were similar to each other in the groups (p>0,05). gerbils were reentrained by the changes in photoperiod nevertheless pinealectomy and melatonin implants did not make any significant influence on this reentrainment (p>0,05). locomotor activity amounts varied in a group-photoperiod-dependent manner. these data suggest that photoperiod but not the pineal gland and constant release melatonin hormone is effective on the activity rhythm of the mongolian gerbil.