HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 92/4/647    most recent expphysiol.2006.036863v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Xu, H.-L. Articles by Pelligrino, D. A. Search for Related Content PubMed PubMed Citation Articles by Xu, H.-L. Articles by Pelligrino, D. A. Related Collections Symposia Papers

¹ Neuroanaesthesia Research Laboratory, University of Illinois at Chicago, IL, USA

Abstract

Owing to their intimate anatomical relationship with cerebral arterioles, astrocytes have been postulated as signal transducers, transferring information from activated neurones to the cerebral microcirculation. These forwarded signals may involve the release of vasoactive factors from the end-feet of astrocytes. This mechanism is termed ‘neurovascular coupling’ and its anatomical components (i.e. neurone, astrocyte and vascular cells) are termed the ‘neurovascular unit’. The process of neurovascular coupling often involves upstream dilatation. This is necessary during periods of increased metabolic demand, in order to permit more blood to reach dilated downstream vessels, thereby improving nutrient supply to the activated neurones. Without it, that downstream dilatation might be ineffective, placing neurones at risk, especially during episodes of intense neuronal activity, such as seizure. In the brain, pial arterioles represent important ‘upstream’ vascular segments. The pial arterioles overlie a thick layer of astrocytic processes, termed the glia limitans. This essentially isolates pial arterioles, anatomically, from the neurones below. Vasodilating signals that originate in the neurones therefore reach the pial arterioles via indirect pathways, primarily involving astrocytes and the glia limitans. Here we discuss a process whereby purinergic mechanisms play a key and neuronal activity-dependent role in astrocyte to astrocyte communication, as well as in glia limitans to pial arteriolar signals leading to vasodilatation.

(Received 21 March 2007; accepted after revision 24 April 2007; first published online 27 April 2007)
Corresponding author H.-L. Xu: University of Illinois at Chicago, Neuroanesthesia Research Laboratory, 835 South Wolcott Avenue, Room E-714E, Chicago, IL 60612 USA. Email: hlxu{at}uic.edu

This article has been cited by other articles:

				H.-L. Xu, L. Mao, S. Ye, C. Paisansathan, F. Vetri, and D. A. Pelligrino Astrocytes are a key conduit for upstream signaling of vasodilation during cerebral cortical neuronal activation in vivo Am J Physiol Heart Circ Physiol, February 1, 2008; 294(2): H622 - H632. [Abstract] [Full Text] [PDF]

				J. A. Filosa Neural glial vascular communication in the brain Exp Physiol, July 1, 2007; 92(4): 633 - 633. [Full Text] [PDF]