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Author Molcan, L.; Sutovska, H.; Okuliarova, M.; Senko, T.; Krskova, L.; Zeman, M. url  doi
  Title Dim light at night attenuates circadian rhythms in the cardiovascular system and suppresses melatonin in rats Type Journal Article
  Year 2019 Publication Life Sciences Abbreviated Journal Life Sci  
  Volume 231 Issue Pages 116568  
  Keywords Animals  
  Abstract AIMS: Cardiovascular parameters exhibit significant 24-h variability, which is coordinated by the suprachiasmatic nucleus (SCN), and light/dark cycles control SCN activity. We aimed to study the effects of light at night (ALAN; 1-2lx) on cardiovascular system control in normotensive rats. MAIN METHODS: Heart rate (HR) and blood pressure (BP) were measured by telemetry during five weeks of ALAN exposure. From beat-to-beat telemetry data, we evaluated spontaneous baroreflex sensitivity (sBRS). After 2 (A2) and 5 (A5) weeks of ALAN, plasma melatonin concentrations and the response of BP and HR to norepinephrine administration were measured. The expression of endothelial nitric oxide synthase (eNOS) and endothelin-1 was determined in the aorta. Spontaneous exploratory behaviour was evaluated in an open-field test. KEY FINDINGS: ALAN significantly suppressed the 24-h variability in the HR, BP, and sBRS after A2, although the parameters were partially restored after A5. The daily variability in the BP response to norepinephrine was reduced after A2 and restored after A5. ALAN increased the BP response to norepinephrine compared to the control after A5. Increased eNOS expression was found in arteries after A2 but not A5. Endothelin-1 expression was not affected by ALAN. Plasma melatonin levels were suppressed after A2 and A5. Spontaneous exploratory behaviour was reduced. SIGNIFICANCE: ALAN decreased plasma melatonin and the 24-h variability in the haemodynamic parameters and increased the BP response to norepinephrine. A low intensity ALAN can suppress circadian control of the cardiovascular system with negative consequences on the anticipation of a load.  
  Address Department of Animal Physiology and Ethology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 0024-3205 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:31202842 Approved no  
  Call Number GFZ @ kyba @ Serial 2548  
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