Int. J. Mol. Sci. 2017, 18(8), 1798; https://doi.org/10.3390/ijms18081798
Aquaporin-4 Functionality and Virchow-Robin Space Water Dynamics: Physiological Model for Neurovascular Coupling and Glymphatic Flow
1
Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Niigata 951-8585, Japan
2
Department of Neurology, University of California, Davis, VANCHCS, Martinez, CA 94553, USA
*
Author to whom correspondence should be addressed.
Received: 23 July 2017 / Revised: 15 August 2017 / Accepted: 16 August 2017 / Published: 18 August 2017
(This article belongs to the Special Issue Cerebral Blood Flow and Metabolism)
Abstract
The unique properties of brain capillary endothelium, critical in maintaining the blood-brain barrier (BBB) and restricting water permeability across the BBB, have important consequences on fluid hydrodynamics inside the BBB hereto inadequately recognized. Recent studies indicate that the mechanisms underlying brain water dynamics are distinct from systemic tissue water dynamics. Hydrostatic pressure created by the systolic force of the heart, essential for interstitial circulation and lymphatic flow in systemic circulation, is effectively impeded from propagating into the interstitial fluid inside the BBB by the tightly sealed endothelium of brain capillaries. Instead, fluid dynamics inside the BBB is realized by aquaporin-4 (AQP-4), the water channel that connects astrocyte cytoplasm and extracellular (interstitial) fluid. Brain interstitial fluid dynamics, and therefore AQP-4, are now recognized as essential for two unique functions, namely, neurovascular coupling and glymphatic flow, the brain equivalent of systemic lymphatics. View Full-TextKeywords:
Hagen-Poiseuille equation; starling resister; rCBF; interstitial flow; glia limitans externa
▼
Figures
Graphical abstract
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
Share & Cite This Article
MDPI and ACS Style
Nakada, T.; Kwee, I.L.; Igarashi, H.; Suzuki, Y. Aquaporin-4 Functionality and Virchow-Robin Space Water Dynamics: Physiological Model for Neurovascular Coupling and Glymphatic Flow. Int. J. Mol. Sci. 2017, 18, 1798.
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.
Related Articles
Article Metrics
Comments
[Return to top]
Int. J. Mol. Sci.
EISSN 1422-0067
Published by MDPI AG, Basel, Switzerland
RSS
E-Mail Table of Contents Alert