1.Comparison of arylalkylamine N-acetyltransferase and melatonin receptor type 1B immunoreactivity between young adult and aged canine spinal cord.
Ji Hyeon AHN ; Joon Ha PARK ; In Hye KIM ; Jae Chul LEE ; Bing Chun YAN ; Min Sik YONG ; Choong Hyun LEE ; Jung Hoon CHOI ; Ki Yeon YOO ; In Koo HWANG ; Seung Myung MOON ; Hyung Cheul SHIN ; Moo Ho WON
Journal of Veterinary Science 2014;15(3):335-342
Melatonin affects diverse physiological functions through its receptor and plays an important role in the central nervous system. In the present study, we compared immunoreactivity patterns of arylalkylamine N-acetyltransferase (AANAT), an enzyme essential for melatonin synthesis, and melatonin receptor type 1B (MT2) in the spinal cord of young adult (2~3 years) and aged (10~12 years) beagle dogs using immunohistochemistry and Western blotting. AANAT-specific immunoreactivity was observed in the nuclei of spinal neurons, and was significantly increased in aged dog spinal neurons compared to young adult spinal neurons. MT2-specific immunoreactivity was found in the cytoplasm of spinal neurons, and was predominantly increased in the margin of the neuron cytoplasm in aged spinal cord compared to that in the young adult dogs. These increased levels of AANAT and MT2 immunoreactivity in aged spinal cord might be a feature of normal aging and associated with a feedback mechanism that compensates for decreased production of melatonin during aging.
Age Factors
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Aging/physiology
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Animals
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Arylalkylamine N-Acetyltransferase/*analysis/immunology/physiology
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Blotting, Western
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Dogs
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Fluorescent Antibody Technique
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Male
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Receptor, Melatonin, MT2/*analysis/immunology/physiology
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Spinal Cord/*chemistry/immunology/physiology
2.Melatonin ameliorates autoimmune encephalomyelitis through suppression of intercellular adhesion molecule-1.
Jong Chul KANG ; Meejung AHN ; Yong Sik KIM ; Changjong MOON ; Yongduk LEE ; Myung Bok WIE ; Young Jae LEE ; Taekyun SHIN
Journal of Veterinary Science 2001;2(2):85-89
Melatonin (N-acetyl-5-methoxytryptamine), a pineal neurohormone, is a hydroxyl radical scavenger and antioxidant, and plays an important role in the immune system. We studied the effect of exogenous melatonin on the pathogenesis of experimental autoimmune encephalomyelitis (EAE). EAE was induced in Lewis rats by immunization with rat spinal cord homogenates. Subsequent oral administration of melatonin at 5 mg/kg significantly reduced the clinical severity of EAE paralysis compared with administration of the vehicle alone (p<0.01). Infiltration of ED1 macrophages and CD4 T cells into spinal cords occurred both in the absence and presence of melatonin treatment, but melatonin-treated rats had less spinal cord infiltration of inflammatory cells than did the control group. ICAM-1 immunoreactivity in the blood vessels of EAE lesions was decreased in melatonin-treated rats compared to vehicle-treated rats. These findings suggest that exogenous melatonin ameliorates EAE via a mechanism involving reduced expression of ICAM-1 and lymphocyte function associated antigen-1a in autoimmune target organs.
Animals
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Encephalomyelitis, Autoimmune, Experimental/*immunology/prevention & control
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Female
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Immunohistochemistry
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Intercellular Adhesion Molecule-1/analysis/*immunology
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Male
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Melatonin/administration & dosage/*physiology
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Rats
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Rats, Inbred Lew
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Spinal Cord/chemistry/pathology