The neurobiology of glia in the context of water and ion homeostasis

被引:456
作者
Simard, M
Nedergaard, M
机构
[1] Utah Diabetes Ctr, Salt Lake City, UT 84108 USA
[2] Univ Rochester, Ctr Aging, Dept Neurosurg, Rochester, NY 14642 USA
关键词
calcium; hormones; blood-brain barrier; transporter; glutamate; gap junction;
D O I
10.1016/j.neuroscience.2004.09.053
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
Astrocytes are highly complex cells that respond to a variety of external stimulations. one of the chief functions of astrocytes is to optimize the interstitial space for synaptic transmission by tight control of water and ionic homeostasis. Several lines of work have, over the past decade, expanded the role of astrocytes and it is now clear that astrocytes are active participants in the tri-partite synapse and modulate synaptic activity in hippocampus, cortex, and hypothalamus. Thus, the emerging concept of astrocytes includes both supportive functions as well as active modulation of neuronal output. Glutamate plays a central role in astrocytic-neuronal interactions. This excitatory amino acid is cleared from the neuronal synapses by astrocytes via glutamate transporters, and is converted into gluatamine, which is released and in turn taken up by neurons. Furthermore, metabotropic glutamate receptor activation on astrocytes triggers via increases in cytosolic Ca2+ a variety of responses. For example, calcium-dependent glutamate release from the astrocytes modulates the activity of both excitatory and inhibitory synapses. In vivo studies have identified the astrocytic end-foot processes enveloping the vessel walls as the center for astrocytic Ca2+ signaling and it is possible that Ca2+ signaling events in the cellular component of the blood-brain barrier are instrumental in modulation of local blood flow as well as substrate transport. The hormonal regulation of water and ionic homeostasis is achieved by the opposing effects of vasopressin and atrial natriuretic peptide on astroglial water and chloride uptake. In conjuncture, the brain appears to have a distinct astrocytic perivascular system, involving several potassium channels as well as aquaporin 4, a membrane water channel, which has been localized to astrocytic endfeet and mediate water fluxes within the brain. The multitask functions of astrocytes are essential for higher brain function. One of the major challenges for future studies is to link receptor-mediated signaling events in astrocytes to their roles in metabolism, ion, and water homeostasis. (C) 2004 IBRO. Published by Elsevier Ltd. All rights reserved.
引用
收藏
页码:877 / 896
页数:20
相关论文
共 248 条
[1]   CHARTING OF TYPE-II GLUCOCORTICOID RECEPTOR-LIKE IMMUNOREACTIVITY IN THE RAT CENTRAL-NERVOUS-SYSTEM [J].
AHIMA, RS ;
HARLAN, RE .
NEUROSCIENCE, 1990, 39 (03) :579-604
[2]   Brain parenchyma vessels and the angiotensin system [J].
Alliot, F ;
Rutin, J ;
Leenen, PJM ;
Pessac, B .
BRAIN RESEARCH, 1999, 830 (01) :101-112
[3]  
Alliot F, 1999, J NEUROSCI RES, V58, P367
[4]   The molecular basis of water transport in the brain [J].
Amiry-Moghaddam, M ;
Ottersen, OP .
NATURE REVIEWS NEUROSCIENCE, 2003, 4 (12) :991-1001
[5]   Delayed K+ clearance associated with aquaporin-4 mislocalization:: Phenotypic defects in brains of α-syntrophin-null mice [J].
Amiry-Moghaddam, M ;
Williamson, A ;
Palomba, M ;
Eid, T ;
de Lanerolle, NC ;
Nagelhus, EA ;
Adams, ME ;
Froehner, SC ;
Agre, P ;
Ottersen, OP .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2003, 100 (23) :13615-13620
[6]   An α-syntrophin-dependent pool of AQP4 in astroglial end-feet confers bidirectional water flow between blood and brain [J].
Amiry-Moghaddam, M ;
Otsuka, T ;
Hurn, PD ;
Traystman, RJ ;
Haug, FM ;
Froehner, SC ;
Adams, ME ;
Neely, JD ;
Agre, P ;
Ottersen, OPT ;
Bhardwaj, A .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2003, 100 (04) :2106-2111
[7]   Intercellular calcium signaling mediated by point-source burst release of ATP [J].
Arcuino, G ;
Lin, JHC ;
Takano, T ;
Liu, C ;
Jiang, L ;
Gao, Q ;
Kang, J ;
Nedergaard, M .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2002, 99 (15) :9840-9845
[8]   Three distinct chloride channels control anion movements in rat parotid acinar cells [J].
Arreola, J ;
Park, E ;
Melvin, JE ;
Begenisich, T .
JOURNAL OF PHYSIOLOGY-LONDON, 1996, 490 (02) :351-362
[9]  
Ballanyi Klaus, 1995, P289
[10]   Alterations in blood pressure and heart rate variability in transgenic rats with low brain angiotensinogen [J].
Baltatu, O ;
Janssen, BJ ;
Bricca, G ;
Plehm, R ;
Monti, J ;
Ganten, D ;
Bader, M .
HYPERTENSION, 2001, 37 (02) :408-413