MelatoninReceptors, MelatoninReceptor, Melatonin, MT1Receptor, Melatonin, MT2Pineal GlandCircadian RhythmArylalkylamine N-AcetyltransferaseTryptaminesAcetylserotonin O-MethyltransferasePhotoperiodLightKynuramineAntioxidantsSleep Disorders, Circadian RhythmSleepDrug Implants5-MethoxytryptamineSeasonsRats, WistarChronobiology DisordersDarknessProlactin