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The source of physiologically stimulated glutamate efflux from the striatum of conscious rats.
Author(s) -
Miele M,
Boutelle M G,
Fillenz M
Publication year - 1996
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1996.sp021805
Subject(s) - microdialysis , glutamate receptor , tetrodotoxin , chemistry , extracellular , striatum , efflux , stimulation , biophysics , medicine , endocrinology , biochemistry , biology , receptor , dopamine
1. Glutamate in the extracellular compartment of the striatum of freely moving rats was monitored at 5 min intervals using microdialysis and an enzyme‐based assay. 2. Basal levels of dialysate glutamate were 3.6 +/‐ 0.5 microM. Local infusion through the dialysis probe of tetrodotoxin (TTX), cadmium chloride or magnesium chloride produced no reduction in basal levels of glutamate; with the latter two there was, instead, an increase. 3. Neuronal activation stimulated by induced grooming was accompanied by an increase in total glutamate efflux of 47.5 +/‐ 25.0% above basal level; this increase was not reduced by local infusion of TTX. 4. We propose that the TTX‐insensitive release of glutamate in response to physiological stimulation is derived from glial cells and is a Ca(2+)‐dependent mechanism triggered by a receptor‐mediated release of Ca2+ from internal stores that spreads through the network of astrocytes.