title: Exacerbated mechanical allodynia in rats with depression-like behavior.
abstract: Although a clinical connection between pain and depression has long been recognized, how these two conditions interact remains unclear. Here we report that both mechanical allodynia and depression-like behavior were significantly exacerbated after peripheral nerve injury in Wistar-Kyoto (WKY) rats, a genetic variation of Wistar rats with demonstrable depression-like behavior. Administration of melatonin into the anterior cingular cortex contralateral to peripheral nerve injury prevented the exacerbation of mechanical allodynia with a concurrent improvement of depression-like behavior in WKY rats. Moreover, there was a lower plasma melatonin concentration and a lower melatonin receptor expression in the anterior cingular cortex in WKY rats than in Wistar rats. These results suggest that there exists a reciprocal relationship between mechanical allodynia and depression-like behavior and the melatoninergic system in the anterior cingular cortex might play an important role in the interaction between pain and depression.
authors.affiliation: MGH Center for Translational Pain Research, Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zeng
authors.forename: Shuxing
authors.initials: S
authors.lastname: Wang
authors.forename: Grewo
authors.initials: G
authors.lastname: Lim
authors.forename: Liling
authors.initials: L
authors.lastname: Yang
authors.forename: Ji
authors.initials: J
authors.lastname: Mao
authors.forename: Backil
authors.initials: B
authors.lastname: Sung
authors.forename: Yang
authors.initials: Y
authors.lastname: Chang
authors.forename: Jeong-Ae
authors.initials: JA
authors.lastname: Lim
authors.forename: Gongshe
authors.initials: G
authors.lastname: Guo
authors.forename: Jianren
authors.initials: J
authors.lastname: Mao
mesh_terms: D000818:Animals; D003866:Depressive Disorder / Q000150:complications* / Q000235:genetics / Q000503:physiopathology; D004195:Disease Models, Animal; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006179:Gyrus Cinguli / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D006930:Hyperalgesia / Q000188:drug therapy / Q000235:genetics* / Q000503:physiopathology; D008297:Male; D008550:Melatonin / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D009437:Neuralgia / Q000188:drug therapy / Q000235:genetics* / Q000503:physiopathology; D017288:Pain Threshold / Q000187:drug effects; D059348:Peripheral Nerve Injuries; D010525:Peripheral Nerves / Q000503:physiopathology; D010523:Peripheral Nervous System Diseases / Q000188:drug therapy / Q000235:genetics / Q000503:physiopathology; D010812:Physical Stimulation; D051381:Rats; D011921:Rats, Inbred WKY; D017208:Rats, Wistar; D044094:Receptors, Melatonin / Q000819:agonists / Q000378:metabolism; D013045:Species Specificity
chemical_list: D044094:Receptors, Melatonin; D008550:Melatonin