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GFAP‐positive hippocampal astrocytes in situ respond to glutamatergic neuroligands with increases in [Ca 2+ ] i
Author(s) -
Porter James T.,
McCarthy Ken D.
Publication year - 1995
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/glia.440130204
Subject(s) - kainate receptor , biology , ampa receptor , astrocyte , glutamate receptor , neuroglia , metabotropic receptor , neuroscience , nmda receptor , glutamatergic , ionotropic effect , hippocampal formation , microbiology and biotechnology , glial fibrillary acidic protein , receptor , metabotropic glutamate receptor , biochemistry , central nervous system , immunology , immunohistochemistry
It is becoming increasingly clear that astrocytes play very dynamic and interactive roles that are important for the normal functioning of the central nervous system. In culture, astrocytes express many receptors coupled to increases in intracellular calcium ([Ca 2+ ] i ). In vivo, it is likely that these receptors are important for the modulation of astrocytic functions such as the uptake of neurotransmitters and ions. Currently, however, very little is known about the expression or stimulation of such astrocytic receptors in vivo. To address this issue, confocal microscopy and calcium sensitive fluorescent dyes were used to examine the dynamic changes in astrocytic [Ca 2+ ] i , within acutely isolated hippocampal slices. Astrocytes were subsequently identified by immunocytochemistry for glial fibrillary acidic protein. In this paper, we present data indicating that hippocampal astrocytes in situ respond to glutamate, kainate, α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionic acid (AMPA), 1‐aminocyclopentane‐trans‐1,3‐dicarboxylic acid (t‐ACPD), N‐methyl‐D‐aspartate (NMDA), and depolarization with increases in [Ca 2+ ] i . The increases in [Ca 2+ ] i occurred in both the astrocytic cell bodies and the processes. Temporally the changes in [Ca 2+ ] i were very dynamic, and various patterns ranging from sustained elevations to oscillations of [Ca 2+ ] i were observed. Individual astrocytes responded to neuroligands selective for both ionotropic and metabotropic glutamate receptors with increases in [Ca 2+ ] i . These findings indicate that astrocytes in vivo contain glutamatergic receptors coupled to increases in [C 2+ ] i and are able to respond to neuronally released neurotransmitters. (c) 1995 Wiley‐Liss, Inc.