title: Association of polymorphism in the human mu-opioid receptor OPRM1 gene with proinflammatory cytokine levels and health perception.
abstract: Recent studies in psychoneuroimmunology have indicated that proinflammatory cytokines cause several diseases and behaviors that overlap symptomatically with depression. It is known that the endogenous opioid peptide beta-endorphin regulates proinflammatory cytokine secretion from peripheral immune cells via mu-opioid receptor-dependent mechanisms. Therefore, it is possible that the functional polymorphism of the mu-opioid receptor gene (OPRM1, SNP: A118G) influences peripheral circulating proinflammatory cytokine levels and the health-related quality of life (QOL) even in healthy populations. In this study, we compared the serum concentrations of several proinflammatory cytokines (interleukin-2 (IL-2), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma)) and the health-related QOL between OPRM1 genotypes. Interestingly, serum concentrations of IL-6, TNF-alpha, and IFN-gamma were significantly lower and the general health score was significantly higher in carriers of the G allele, who show a strong binding of beta-endorphin to the mu-opioid receptor as compared to individuals without the G allele. Correlation analysis indicated that the general health score was negatively correlated with the IL-6 serum concentration. These results suggest that the sensitive endogenous opioid system in carriers of the G allele may suppress proinflammatory cytokine secretion from peripheral immune cells; consequently, it may influence the health perception.
authors.affiliation: Department of Neurology Psychosomatic Medicine, Ban Buntane Hotokukai Hospital, School of Medicine, Fujita Health University, Aichi 454-8509, Japan. matsunag@fujita-hu.ac.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Matsunaga
authors.forename: Tokiko
authors.initials: T
authors.lastname: Isowa
authors.forename: Hiroki
authors.initials: H
authors.lastname: Murakami
authors.forename: Kunio
authors.initials: K
authors.lastname: Kasugai
authors.forename: Masashi
authors.initials: M
authors.lastname: Yoneda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kaneko
authors.forename: Hideki
authors.initials: H
authors.lastname: Ohira