Melatonin treatment during early life interacts with restraint to alter neuronal morphology and provoke depressive-like responses.
Stressors during early life induce anxiety- and depressive-like responses in adult rodents. Siberian hamsters (Phodopus sungorus) exposed to short days post-weaning also increase adult anxiety- and depressive-like behaviors. To test the hypothesis that melatonin and exposure to stressors early in life interact to alter adult affective responses, we administered melatonin either during the perinatal (gestational day 7 to postnatal day 14) or postnatal (day 15-56) periods and also exposed a subset of dams to restraint during gestation (1 h-2×/day for 4 days). During the final week of injections, depressive-like behaviors were assessed using the sucrose anhedonia and forced swim tests. Hamsters exposed to prenatal restraint and treated with melatonin only during the postnatal period increased depressive-like responses in the forced swim test relative to all other groups. Offspring from restrained dams increased the number of fecal boli produced during the forced swim test, an anxiety-like response. In the present study, prenatal restraint reduced CA1 dendritic branching overall and perinatal melatonin protected hamsters from this restraint-induced reduction. These results suggest that the photoperiodic conditions coincident with birth and early life stressors are important in the development of adult affective responses.
Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA. Electronic address: taryn.aubrecht@osumc.edu.
Taryn G
TG
Aubrecht
Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
Zachary M
ZM
Weil
Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
Randy J
RJ
Nelson
D059445:Anhedonia / Q000502:physiology; D000818:Animals; D001007:Anxiety / Q000473:pathology / Q000503:physiopathology; D056547:CA1 Region, Hippocampal / Q000254:growth & development* / Q000473:pathology / Q000503:physiopathology*; D006224:Cricetinae; D003712:Dendrites / Q000473:pathology / Q000502:physiology; D003866:Depressive Disorder / Q000473:pathology / Q000503:physiopathology*; D019422:Dietary Sucrose; D005260:Female; D008297:Male; D008550:Melatonin / Q000378:metabolism*; D009474:Neurons / Q000473:pathology* / Q000502:physiology; D017111:Phodopus; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000473:pathology / Q000503:physiopathology; D012149:Restraint, Physical; D013315:Stress, Psychological / Q000473:pathology / Q000503:physiopathology*; D013550:Swimming
D019422:Dietary Sucrose; D008550:Melatonin
Hippocampus; Melatonin; Seasonal affective disorder; Seasonality; Stress