Calcium green-5N, a novel fluorescent probe for monitoring high intracellular free Ca2+ concentrations associated with glutamate excitotoxicity in cultured rat brain neurons.
We describe here the properties of calcium green-5N (CG5N), a novel Ca(2+)-sensitive fluorescent probe. CG5N binds Ca2+ with an affinity of 4.29 +/- 0.67 microM. Ca2+ binding is associated with a 14.7-fold increase in fluorescence. Mg2+ binds to CG5N with an affinity of 5 mM but produces a very small change in fluorescence. Using CG5N [Ca2+]i was recorded in single cultured neurons from fetal rat forebrain. Glutamate together with glycine increased [Ca2+]i by 1.17 +/- 0.15 microM. Pretreating cells with 5 mM potassium cyanide significantly potentiated the response to glutamate, resulting in a mean increase of 8.8 +/- 2 microM. These results demonstrate that CG5N is a useful indicator for measuring very large changes in [Ca2+]i in neurons.
Rajdev
S
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Department of Pharmacology, University of Pittsburgh, PA 15261.
Reynolds
I J
IJ
D000818:Animals; D001923:Brain Chemistry / Q000502:physiology; D002545:Brain Ischemia / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003486:Cyanides / Q000494:pharmacology; D005456:Fluorescent Dyes; D005971:Glutamates / Q000633:toxicity*; D018698:Glutamic Acid; D005998:Glycine / Q000633:toxicity; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009930:Organic Chemicals; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects
D003486:Cyanides; D005456:Fluorescent Dyes; D005971:Glutamates; D009930:Organic Chemicals; D016194:Receptors, N-Methyl-D-Aspartate; C071336:calcium green; D018698:Glutamic Acid; D002118:Calcium; D005998:Glycine