4 years ago

Robust circadian clock oscillation and osmotic rhythms in inner medulla reflecting cortico-medullary osmotic gradient rhythm in rodent kidney

Hitoshi Inokawa, Tetsuro Kusaba, Yoshiki Tsuchiya, Nobuya Koike, Kazuhiro Yagita, Yasuhiro Umemura, Keiichi Tamagaki, Munehiro Ohashi, Yoichi Minami, Masayuki Hara
Circadian clocks in mammals function in most organs and tissues throughout the body. Various renal functions such as the glomerular filtration and excretion of electrolytes exhibit circadian rhythms. Although it has been reported that the expression of the clock genes composing molecular oscillators show apparent daily rhythms in rodent kidneys, functional variations of regional clocks are not yet fully understood. In this study, using macroscopic bioluminescence imaging method of the PER2::Luciferase knock-in mouse kidney, we reveal that strong and robust circadian clock oscillation is observed in the medulla. In addition, the osmotic pressure in the inner medulla shows apparent daily fluctuation, but not in the cortex. Quantitative-PCR analysis of the genes contributing to the generation of high osmotic pressure or the water re-absorption in the inner medulla, such as vasopressin receptors (V1aR, V2R), urea transporter (UT-A2) and water channel (Aqp2) show diurnal variations as well as clock genes. Deficiency of an essential clock gene Bmal1 impairs day-night variations of osmotic pressure gradient in the inner medulla, suggesting that circadian clocks in the medulla part of the kidney may regulate the circadian rhythm of cortico-medullary osmotic pressure gradient, and may contribute physiological day-night rhythm of urination.

Publisher URL: https://www.nature.com/articles/s41598-017-07767-8

DOI: 10.1038/s41598-017-07767-8

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.