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Calcium Transport by Primary Cultured Neuronal and Glial Cells from Chick Embryo Brain
Author(s) -
Barnes Eugene M.,
Mandel P.
Publication year - 1981
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1981.tb02380.x
Subject(s) - calcium , verapamil , potassium , depolarization , chemistry , neuron , sodium , tetrodotoxin , endocrinology , medicine , biochemistry , biophysics , biology , neuroscience , organic chemistry
The uptake of calcium was examined in primary cultures of pure neurons and of glial cells from dissociated hemispheres of chick embryo brain. Neuronal cultures took up calcium at a rate of 2.0 nmol per min per mg cell protein at medium concentrations of 1.2 mM‐Ca 2+ and 5.4 mM‐K + . The rate of calcium entry into neurons was increased 2.7‐fold by elevating medium potassium to 60 MM. The effect of high external potassium was to increase the V max value for calcium transport from 5.5 to 13 nmol per min per mg; the Michaelis constant for calcium, 1.2 mM, was unchanged. The potassium‐dependent component of calcium entry into the neuronal cultures was eliminated by addition of 0.1 mM‐D‐600 (a verapamil derivative) or by 1 mM‐CoCl 2 , but 0.5 μM‐tet‐rodotoxin had no significant effect. When choline replaced potassium in uptake medium no change in calcium transport was detected in neurons, nor was the entry of calcium increased when choline replaced sodium. Glial cultures took up calcium at 20% of the basal rate for neuronal cultures on a weight‐of‐protein basis. Uptake was not increased by potassium; during depolarization by potassium the calcium transport activity of glia was less than 10% that of neurons. It was concluded that cultured neurons contain a depolarization‐sensitive, calcium‐specific channel. A similar calcium transport activity was not detected in cultured glial cells.