[Role of melatonin receptors in spatial learning of rats exposed to continuous light]

ABSTRACT

During critical period of mammal's CNS development, interaction of genetic and experience driven processes affects almost their all behaviors in adolescence. The aim of this study was to assess interaction of melatonin and its antagonist, Luzindole on the spatial learning and memory of the rats [Morris Water Maze [MWM]] exposed to continuous light. This experimental study included sixty 45-day-old male rats which were randomly allocated in two groups; control group went through cycles of 12 hours in light/12 hours in dark from birth to the end of the study and the light exposed group was reared in light. Each group also, had 3 subgroups control, receiving melatonin and receiving luzindole [n=10 for every group]. Using MWM, the animals learning and memory was tested for 5 days. Our results indicated that in the learning phase, the light exposed animals spent more time to find the hidden platform than the control group. Luzindole improved the learning ability in light exposed animals. Melatonin also, slackens the spatial learning of the control animals. luzindole improved spatial learning of the light exposed rats. Light exposure and melatonin had no effect on the memory of these animals. Luzindole only caused a disturbance in spatial memory of the rats in the control group. Light exposure and melatonin impair rat's spatial learning. Non of these two interventions influenced spatial learning of the rats