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Characterization of nerve growth factor binding to embryonic rat spinal cord neurons
Author(s) -
Marchetti D.,
McManaman J. L.
Publication year - 1990
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490270211
Subject(s) - embryonic stem cell , spinal cord , nerve growth factor , microbiology and biotechnology , neuroscience , biology , anatomy , receptor , genetics , gene
The binding of iodinated β‐nerve growth factor, [ 125 I]‐NGF, to embryonic (E16) rat spinal cord cells, was investigated to characterize the binding properties and cellular distribution of nerve growth factor receptors. Spinal cord cells prepared without trypsin yielded two classes of NGF binding sites with Kd's of 3 × 10 −11 M and 4 × 10 −9 M. Fractionation of the cells by discontinuous gradients composed of 8%, 12%, and 17% metrizamide was used to separate motoneurons from other cell types. The motoneuron enriched fraction (8% metrizamide) contained approximately 10% of the cells and 64% of the choline acetyltransferase (ChAT) activity. In contrast, the 12% metrizamide fraction contained most (51%) of the cells and 36% of the ChAT activity, while the 17% metrizamide fraction contained the remainder of the cells and negligible amounts of ChAT activity. Characterization of [ 125 I]‐NGF binding to each metrizamide fraction showed that the motoneuron‐en‐riched fraction exhibited both high and low affinity binding sites, while the other metrizamide fractions exhibited only the low affinity binding sites. These findings indicate that although low affinity NGF receptors appear to be relatively evenly distributed amongst embryonic rat spinal cord cells, high affinity NGF receptors are found primarily on motoneurons.