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Catecholaminergic cells and support cell precursors in neural crest cultures differentially express nerve growth factor receptors
Author(s) -
Bernd Paulette
Publication year - 1989
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1016/0736-5748(89)90005-1
Subject(s) - nerve growth factor , catecholaminergic , neural crest , tyrosine hydroxylase , biology , microbiology and biotechnology , catecholaminergic cell groups , receptor , medicine , endocrinology , immunocytochemistry , embryonic stem cell , cell culture , catecholamine , embryo , biochemistry , dopamine , genetics , gene
Long‐term neural crest cultures grown in the continuous absence of exogenous nerve growth factor (NGF) contain a subpopulation of cells with NGF receptors exclusively of the low affinity subtype ( d of approximately 3.2 nM). The current studies combined immunocytochemistry, using GIN1 (a support cell marker) or tyrosine hydroxylase antibodies, with radioautography following exposure to iodinated nerve growth factor ( 125 I‐NGF). The majority of cells specifically binding 125 I‐NGF were found to be immunoreactive for GIN1, indicating that the primary cell phenotype expressing receptors for NGF appear to be support cell precursors, at least under these conditions. These cells are likely to be responsive to and/or dependent upon NGF; the nature of this response or dependency remains to be determined. Some cells exhibiting silver grains were not immunoreactive for GIN 1, suggesting that other cell phenotypes in neural crest cultures also have NGF receptors. In addition, some neural crest cells were found that stained with GIN1 and lacked 125 I‐NGF binding. Tyrosine hydroxylase‐like immunoreactive cells apparently did not bind 125 1‐NGF under these culture conditions. Catecholaminergic sympathetic and sensory neurons from embryonic ganglia, derived from the neural crest, express both the high and low affinity forms of the NGF receptor. In order to determine whether the microenvironment played a role in the type of Catecholaminergic cells appearing in culture, neural crest cells were grown in the continuous presence of exogenous NGF. Under these conditions, many tyrosine hydroxylase‐like immunoreactive cells were found that specifically bound 125 I‐NGF. In addition, silver grains were still detected on these cells following a chase with nonradioactive NGF, designed to eliminate 125 I‐NGF bound to low affinity sites. Therefore, the Catecholaminergic cells possess both the low and high affinity forms of the receptor. NGF's ability to modulate tyrosine hydroxylase activity, as it does in mature Catecholaminergic neurons, was tested in this system. Surprisingly, there was no statistically significant difference in tyrosine hydroxylase activity in cultures grown in the absence or presence of exogenous NGF. This raises the possibility that embryonic Catecholaminergic cells are unable to respond to NGF in this specific way, even though the receptors for the factor are present.