title: MT1 receptor expression and AA-NAT activity in lymphatic tissue following melatonin administration in male golden hamster.
abstract: Exogenous melatonin as a marker of the chemical expression of darkness is playing a key role in the synchronization of circadian functions and seasonal biological rhythms. Our study was designed to elucidate whether melatonin treatment can modulate the melatonin synthesis via the rate limiting enzyme arylalkylamine-N-acetyltransferase (AA-NAT) in spleen, thymus and bone marrow thereby the proliferation rate of splenocytes, thymocytes and bone marrow mononuclear cells (BM-MNCs) of golden hamsters. The AA-NAT activity in different lymphoid tissue documented the synthesis of melatonin in those organs. Exogenous melatonin treatment to hamsters enhanced the AA-NAT activity in spleen and thymus along with an increase in the inflammatory response by DTH reactions that could be related to the increased level of interleukin-2 and IFN-γ by T lymphocytes in serum/culture medium, proliferation rate and expression of melatonin membrane receptor MT(1). Thus, the relevance of melatonin synthesis by lymphatic tissues might be maintaining surveillance and local defence responses.
authors.affiliation: Pineal Research Lab, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India.
authors.forename: Dipanshu Kumar
authors.initials: DK
authors.lastname: Vishwas
authors.affiliation: Pineal Research Lab, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India. Electronic address: chaldar2001@yahoo.com.
authors.forename: Chandana
authors.initials: C
authors.lastname: Haldar
mesh_terms: D000818:Animals; D047068:Arylalkylamine N-Acetyltransferase / Q000378:metabolism*; D001853:Bone Marrow / Q000276:immunology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D006224:Cricetinae; D006968:Hypersensitivity, Delayed / Q000276:immunology*; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D008550:Melatonin / Q000008:administration & dosage*; D044122:Receptor, Melatonin, MT1 / Q000235:genetics / Q000378:metabolism*; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology; D015854:Up-Regulation
chemical_list: D007376:Interleukin-2; D044122:Receptor, Melatonin, MT1; D007371:Interferon-gamma; D047068:Arylalkylamine N-Acetyltransferase; D008550:Melatonin
keywords: AA-NAT activity; BM-MNCs; Blastogenic response; MT(1) receptor; Melatonin