title: Effect of melatonin on blood pressure and nitric oxide generation in rats with metabolic syndrome.
abstract: Melatonin, a multitasking indolamine, seems to be involved in a variety of physiological and metabolic processes via both receptor-mediated and receptor-independent mechanisms. The aim of our study was to find out whether melatonin can affect blood pressure (BP), nitric oxide synthase (NOS) activity, eNOS and nNOS protein expressions in rats with metabolic syndrome (SHR/cp). Rats were divided into four groups: 6-week-old male WKY andSHR/cp and age-matched WKY and SHR/cp treated with melatonin (10 mg/kg/day) for 3 weeks. BP was measured by tail-cuff plethysmography. NOS activity, eNOS and nNOS protein expressions were determined in the heart, aorta, brain cortex and cerebellum. MT(1) receptors were analyzed in the brain cortex and cerebellum. In SHR/cp rats, BP was decreased after melatonin treatment. In the same group, melatonin did not affect NOS activity and eNOS protein expression in the heart and aorta, while it increased both parameters in the brain cortex and cerebellum. Interestingly, melatonin elevated MT1 protein expression in the cerebellum. Neuronal NOS protein expression was not changed within the groups. In conclusion, increased NOS activity/eNOS upregulation in particular brain regions may contribute partially to BP decrease in SHR/cp rats after melatonin treatment. Participation of MT(1) receptors in this melatonin action may be supposed.
authors: Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Bratislava, Slovak Republic. olga.pechanova@savba.sk.
authors: J
authors: J
authors: Klimentova
authors: M
authors: M
authors: Cebova
authors: A
authors: A
authors: Barta
authors: Z
authors: Z
authors: Matuskova
authors: S
authors: S
authors: Vrankova
authors: R
authors: R
authors: Rehakova
authors: M
authors: M
authors: Kovacsova
authors: O
authors: O
authors: Pechanova
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001921:Brain / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008550:Melatonin / Q000008:administration & dosage*; D024821:Metabolic Syndrome / Q000503:physiopathology*; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D014018:Tissue Distribution
chemical_list: D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D008550:Melatonin