Klimentova J, Cebova M, Barta A, Matuskova Z, Vrankova S, Rehakova R, Kovacsova M, Pechanova O
Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
Physiol Res. 2016 Oct 24;65(Suppl 3):S373-S380. doi: 10.33549/physiolres.933436.
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.
褪黑素是一种具有多种功能的吲哚胺，似乎通过受体介导和非受体依赖机制参与多种生理和代谢过程。我们研究的目的是探究褪黑素是否会影响代谢综合征大鼠（SHR/cp）的血压（BP）、一氧化氮合酶（NOS）活性、内皮型一氧化氮合酶（eNOS）和神经元型一氧化氮合酶（nNOS）蛋白表达。将大鼠分为四组：6周龄雄性WKY和SHR/cp，以及与之年龄匹配的经褪黑素（10毫克/千克/天）处理3周的WKY和SHR/cp。通过尾套体积描记法测量血压。测定心脏、主动脉、大脑皮层和小脑中的NOS活性、eNOS和nNOS蛋白表达。分析大脑皮层和小脑中的MT(1)受体。在SHR/cp大鼠中，褪黑素治疗后血压降低。在同一组中，褪黑素不影响心脏和主动脉中的NOS活性和eNOS蛋白表达，而在大脑皮层和小脑中则增加了这两个参数。有趣的是，褪黑素提高了小脑中MT1蛋白的表达。各组内神经元型NOS蛋白表达未发生变化。总之，特定脑区中NOS活性增加/eNOS上调可能部分导致了褪黑素治疗后SHR/cp大鼠血压降低。可以推测MT(1)受体参与了褪黑素的这一作用。
