Limits...
Virchow-Robin space and aquaporin-4: new insights on an old friend.

Nakada T - Croat. Med. J. (2014)

Bottom Line: Autoregulation of brain blood flow serves to maintain a constant inner capillary fluid pressure, allowing fluid pressure of the Virchow Robin space to regulate regional cerebral blood flow (rCBF) based on AQP-4 gating.Excess heat produced by neural activities is effectively removed from the area of activation by increased rCBF by closing AQP-4 channels.This neural flow coupling (NFC) is likely mediated by heat generated proton channels.

View Article: PubMed Central - PubMed

Affiliation: Tsutomu Nakada, Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, 1-757 Asahimachi, Niigata, 951-8585, Japan, tnakada@bri.niigata-u.ac.jp.

ABSTRACT
Recent studies have strongly indicated that the classic circulation model of cerebrospinal fluid (CSF) is no longer valid. The production of CSF is not only dependent on the choroid plexus but also on water flux in the peri-capillary (Virchow Robin) space. Historically, CSF flow through the Virchow Robin space is known as interstitial flow, the physiological significance of which is now fully understood. This article briefly reviews the modern concept of CSF physiology and the Virchow-Robin space, in particular its functionalities critical for central nervous system neural activities. Water influx into the Virchow Robin space and, hence, interstitial flow is regulated by aquaporin-4 (AQP-4) localized in the endfeet of astrocytes, connecting the intracellular cytosolic fluid space of astrocytes and the Virchow Robin space. Interstitial flow has a functionality equivalent to systemic lymphatics, on which clearance of β-amyloid is strongly dependent. Autoregulation of brain blood flow serves to maintain a constant inner capillary fluid pressure, allowing fluid pressure of the Virchow Robin space to regulate regional cerebral blood flow (rCBF) based on AQP-4 gating. Excess heat produced by neural activities is effectively removed from the area of activation by increased rCBF by closing AQP-4 channels. This neural flow coupling (NFC) is likely mediated by heat generated proton channels.

Show MeSH

Related in: MedlinePlus

Simulation architecture.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4157385&req=5

Figure 7: Simulation architecture.

Mentions: Schematic presentation of temperature changes-associated activation. A detailed description of simulation study can be found in the Methods. The figure shows temperature changes of the activated area (Figure 7) with continuous neural activities in seconds and associated percentage of cerebral blood flow (CBF) increase. Note that with 34.5% increase in CBF, virtually 100% of excess heat can be removed from the cortex.


Virchow-Robin space and aquaporin-4: new insights on an old friend.

Nakada T - Croat. Med. J. (2014)

Simulation architecture.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4157385&req=5

Figure 7: Simulation architecture.
Mentions: Schematic presentation of temperature changes-associated activation. A detailed description of simulation study can be found in the Methods. The figure shows temperature changes of the activated area (Figure 7) with continuous neural activities in seconds and associated percentage of cerebral blood flow (CBF) increase. Note that with 34.5% increase in CBF, virtually 100% of excess heat can be removed from the cortex.

Bottom Line: Autoregulation of brain blood flow serves to maintain a constant inner capillary fluid pressure, allowing fluid pressure of the Virchow Robin space to regulate regional cerebral blood flow (rCBF) based on AQP-4 gating.Excess heat produced by neural activities is effectively removed from the area of activation by increased rCBF by closing AQP-4 channels.This neural flow coupling (NFC) is likely mediated by heat generated proton channels.

View Article: PubMed Central - PubMed

Affiliation: Tsutomu Nakada, Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, 1-757 Asahimachi, Niigata, 951-8585, Japan, tnakada@bri.niigata-u.ac.jp.

ABSTRACT
Recent studies have strongly indicated that the classic circulation model of cerebrospinal fluid (CSF) is no longer valid. The production of CSF is not only dependent on the choroid plexus but also on water flux in the peri-capillary (Virchow Robin) space. Historically, CSF flow through the Virchow Robin space is known as interstitial flow, the physiological significance of which is now fully understood. This article briefly reviews the modern concept of CSF physiology and the Virchow-Robin space, in particular its functionalities critical for central nervous system neural activities. Water influx into the Virchow Robin space and, hence, interstitial flow is regulated by aquaporin-4 (AQP-4) localized in the endfeet of astrocytes, connecting the intracellular cytosolic fluid space of astrocytes and the Virchow Robin space. Interstitial flow has a functionality equivalent to systemic lymphatics, on which clearance of β-amyloid is strongly dependent. Autoregulation of brain blood flow serves to maintain a constant inner capillary fluid pressure, allowing fluid pressure of the Virchow Robin space to regulate regional cerebral blood flow (rCBF) based on AQP-4 gating. Excess heat produced by neural activities is effectively removed from the area of activation by increased rCBF by closing AQP-4 channels. This neural flow coupling (NFC) is likely mediated by heat generated proton channels.

Show MeSH
Related in: MedlinePlus