Glutamate stimulates release of Ca2+ from internal stores in astroglia.
We report here that, in the absence of external Ca2+, glutamate produces a transient increase in intracellular Ca2+ [( Ca2+]i) in cultured spinal cord astrocytes, by mobilizing internal Ca2+ stores. [Ca2+]i was measured with Fura-2 using the ratiometric method. Astrocytes were identified by immunostaining for glial fibrillary acidic protein. Glutamate and quisqualate consistently caused a transient increase in [Ca2+]i, with both the response amplitude and latency being graded functions of agonist concentration. Some cells produced multiple transients. N-Methyl-D-aspartate, kainate and aspartate were ineffective. We conclude that the quisqualate subtype of glutamate receptors mediates release of Ca2+ from internal stores in mammalian astrocytes.
Ahmed
Z
Z
Department of Physiology, State University of New York, Buffalo 14214.
Lewis
C A
CA
Faber
D S
DS
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D001572:Benzofurans; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D005456:Fluorescent Dyes; D016257:Fura-2; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005971:Glutamates / Q000494:pharmacology*; D018698:Glutamic Acid; D007150:Immunohistochemistry; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D051381:Rats; D018091:Receptors, AMPA; D017981:Receptors, Neurotransmitter / Q000187:drug effects*; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism*
D001572:Benzofurans; D005456:Fluorescent Dyes; D005904:Glial Fibrillary Acidic Protein; D005971:Glutamates; D018377:Neurotransmitter Agents; D018091:Receptors, AMPA; D017981:Receptors, Neurotransmitter; D018698:Glutamic Acid; D002118:Calcium; D016257:Fura-2