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Calcium waves in dissociated retinal glial (Müller) cells are evoked by release of calcium from intracellular stores
Author(s) -
Keirstead Susan A.,
Miller Robert F.
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.440140104
Subject(s) - extracellular , calcium , ryanodine receptor , biology , calcium in biology , intracellular , t type calcium channel , fura 2 , microbiology and biotechnology , biophysics , voltage dependent calcium channel , medicine , biochemistry , enzyme , cytosol
Calcium imaging techniques were used to study intracellular free calcium ion regulation in isolated Müller cells in response to changes in extracellular potassium concentration and to caffeine and ryanodine. Müller cells were dissociated from the adult tiger salamander ( Ambystoma tigrinum) retina and studied using the calcium indicator Fura‐2 and video imaging microscopy techniques. Our results demonstrate that elevation of extracellular potassium in the presence of extracellular calcium evokes an increase in intracellular calcium ([Ca 2+ ] i ) throughout the length of the Müller cell. In contrast, in the absence of extracellular calcium, elevation of extracellular potassium can trigger a long latency, wave‐like increase in [Ca 2+ ] i that begins in the apical region of the Müller cell and moves toward the endfoot. A similar calcium wave can be evoked in Müller cells when they are exposed to caffeine or ryanodine, agents that cause release of calcium from intracellular stores in many cell types. These data suggest that [Ca 2+ ] i may be altered in Müller cells through an extracellular pathway as well as through a ryanodine‐sensitive intracellular release mechanism. The functional consequences of these changes in [Ca 2+ ] i remain to be elucidated. © 1995 Wiley‐Liss, Inc.