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Glutamate‐induced calcium signaling in astrocytes
Author(s) -
Kim Warren T.,
Rioult Marika G.,
CornellBell Ann H.
Publication year - 1994
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.440110211
Subject(s) - metabotropic receptor , ionotropic effect , biology , metabotropic glutamate receptor , intracellular , glutamate receptor , neuroscience , excitatory postsynaptic potential , calcium signaling , depolarization , calcium in biology , microbiology and biotechnology , biophysics , receptor , inhibitory postsynaptic potential , biochemistry
Astrocytes respond to the excitatory neurotransmitter glutamate with dynamic spatio‐temporal changes in intracellular calcium [Ca 2+ ] i . Although they share a common wave‐like appearance, the different [Ca 2+ ] i changes‐‐an initial spike, sustained elevation, oscillatory intracellular waves, and regenerative intercellular waves‐‐are actually separate and distinct phenomena. These separate components of the astrocytic Ca 2+ response appear to be generated by two different signal transduction pathways. The metabotropic response evokes an initial spatial Ca 2+ spike that can propagate rapidly from cell to cell and appears to involve IP 3 . The metabotropic response can also produce oscillatory intracellular waves of various amplitudes and frequencies that propagate within cells and are sustained only in the presence of external Ca 2+ . The ionotropic response, however, evokes a sustained elevation in [Ca 2+ ] i associated with receptor‐mediated Na + and Ca 2+ influx, depolarization, and voltage‐dependent Ca 2+ influx. In addition, the ionotropic response can lead to regenerative intercellular waves that propagate smoothly and nondecrementally from cell to cell, possibly involving Na + /Ca 2+ exchange. All these astrocytic [Ca 2+ ] i changes tend to appear wave‐like, traveling from region to region as a transient rise in [Ca 2+ ] i . Nevertheless, as our understanding of the cellular events that underlie these [Ca 2+ ] i changes grows, it becomes increasingly clear that glutamate‐induced Ca 2+ signaling is a composite of separate and distinct phenomena, which may be distinguished not based on appearance alone, but rather on their underlying mechanisms. © 1994 Wiley‐Liss, Inc.