Journal of Neuroscience, Vol 6, 2543-2550, Copyright © 1986 by Society for Neuroscience
Nerve growth factor receptors on chick embryo sympathetic ganglion cells: binding characteristics and development
EW Godfrey and EM Shooter
NGF is essential for the development and maintenance of sympathetic and
certain sensory neurons. The NGF receptors on the surface of sympathetic
ganglion cells from chick embryos were characterized; they consist of
high-affinity receptors with a dissociation constant of about 10(-11) M,
and low-affinity receptors with a dissociation constant of about 10(-9) M.
There are more than 10 times as many low- affinity as high-affinity
receptors per cell. The heterogeneity of NGF binding is not due to
negatively cooperative interactions among the receptors. The high- and
low-affinity components of NGF binding defined at steady state correspond
to slowly and rapidly dissociating components of bound NGF seen in kinetic
experiments. In addition, a very slowly dissociating component of bound NGF
was observed; this component was a small fraction of binding at low
concentrations of NGF but increased to 20-60% of bound NGF at the highest
NGF concentrations examined. This very slowly dissociating component of
bound NGF accounts for several peculiarities in the binding data not
accounted for by steady-state binding of NGF to its high- and low-affinity
receptors. Developmental studies showed that both high- and low-affinity
NGF receptors were present on chick embryo sympathetic ganglion cells from
6.5 to 20 d in ovo. No significant differences in the numbers or affinities
of the receptors were seen with cells from ganglia at 9, 11, or 15 d of
development. Cultured non-neuronal cells from sympathetic ganglia had only
low-affinity NGF receptors.
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