Nerve growth factor treatment does not prevent dorsal root ganglion cell death induced by target removal in chick embryos

A subpopulation of chicken primary sensory neurons defined by complete co-localization of peripherin-and ovalbumin-immunoreactivities

In a previous study, we have demonstrated that an ovalbumin-like antigen is present within approximately one-half of all neurons of chicken spinal ganglia. The current study demonstrates this antigen co-localizes absolutely with neural intermediate filament protein (Peripherin) in small to medium-sized neurons of spinal ganglia. While the function of ovalbumin in neurons is unknown, its precise co-localization with Peripherin suggests a functional role restricted to neurons of a defined phenotype.

Electron microscopic immunocytochemical localization of nerve growth factor in developing mouse olfactory neurons

The immunocytochemical localization of nerve growth factor (NGF) in the embryonic mouse has been examined using correlative light and electron microscope procedures. In flat-embedded thick sections, primary sensory neurons of the olfactory pathway were clearly visible by their high level of NGF-like immunoreactivity. When ultrathin sections were examined under the electron microscope, the HRP reaction product present in the nasal epithelium was confined to the cytoplasm of the chemoreceptor cells, including the dendrites projecting into the nasal cavity. The axons projecting to the olfactory bulb and axon bundles within the bulb were also stained specifically for NGF. The reaction product did not appear to be associated with any particular subcellular structure. Neither the columnar supporting cells nor the basal precursor cells showed any evidence of immunoreactivity. No evidence was found for the presence of NGF in cells such as epithelial or glial cells within the immediate environment of the receptor neurons. These first subcellular localization studies indicate the presence of high levels of NGF in neurons not known to be sensitive to the trophic molecule.

Endogenous chicken nerve growth factor from sheath cells is transported in regenerating nerve

We report the presence of endogenous nerve growth factor (NGF) in chicken peripheral nerve. The molecule has been detected with antibodies to mouse salivary gland NGF, using immunohistochemical and immunoelectrophoretic techniques. Previous studies have shown that these antibodies inhibit the survival activity of extracts of chicken peripheral nerve. The NGF accumulated distal, but not proximal, to a ligature placed on a peripheral sympathetic nerve demonstrating that it was retrogradely transported. This transport was detected in intact nerve fibers as well as in nerves from which the peripheral target had been ablated 6 hr or 7 days previously. The results indicate that avian NGF is present in adult chicken peripheral nerves and that this molecule shares antigenic determinants with the mouse molecule. The results further demonstrate that regenerating neurons retrogradely transport NGF supplied by cells within the peripheral nerve (presumably Schwann). The possibility that these cells also provide NGF to intact neurons is discussed.

Immunohistochemical evidence for the distribution of nerve growth factor in the embryonic mouse

The distribution of nerve growth factor-like immunoreactivity has been examined in the embryonic mouse with special reference to the CNS. The intensity of the immunoreactive stain was found to be greatest on embryonic days 15 and 16. The antigen is widespread and present in high concentrations in both the PNS and CNS. Most intense staining was detected in cranial nerve tracts, hippocampus, developing white matter of the spinal cord and tegmentum. Lower intensities were found within diencephalic regions, spinal cord grey matter, medullary fibre tracts and cerebellum. These results support the increasing evidence suggesting that the trophic molecule nerve growth factor has an important role to play in the development of central as well as peripheral neurons.

Effects of nerve growth factor on sensory neurons in the chick embryo: a stereological study

Chicken embryos on days 6-13 of incubation received injections of purified beta NGF (80 micrograms/day) for 3 or 4 days and were then killed. Sensory ganglia were fixed and taken for embedding and sectioning. A stereological method based on unfolding of cell-diameter frequencies was used to determine the number of neurons of different size in the spinal, trigeminal and nodose ganglia. The total volume of the ganglia was also determined. NGF induced increases in diameter of the neural crest-derived dorsomedial (DM) neurons in spinal and trigeminal ganglia. Injected NGF did not influence ventrolateral (VL) neurons of neural crest origin in the spinal ganglia nor the ventrolateral neurons of placodal origin in the trigeminal ganglion. The volumes of spinal and trigeminal ganglia increased by 50 and 100%, respectively. The volume of the nodose ganglion and the total number and size of the placodal nodose neurons were unaffected by NGF. The results demonstrate a clear difference in the response to NGF in vivo between smaller and larger sensory neurons.

Nerve growth factor immunohistochemistry and biological activity in the rat iris

Nerve growth factor (NGF) production in the cultured rat iris was examined using immunohistochemistry and bioassay of irides and conditioned media. NGF immunoreactivity increased steadily with days in culture so that the intensity of staining was maximal after 6 days of culture. The localization was shown to be sensitive to the presence of cross-linking fixatives such as formaldehyde and glutaraldehyde and this effect was only partially alleviated by the use of very high concentrations of antibodies. NGF immunoreactivity was localized in Schwann cells and possibly nerve axons, but with no antigen detectable in smooth muscle fibres. Media conditioned over irides initially supported a high percentage of dissociated sympathetic neurons, but the number supported decreased with time in culture until day 4. Moreover, the use of antibodies to NGF allowed the detection of at least two types of neuronotropic activity, NGF accounting for at least 94% of the total trophic activity present after 4 days of culture. These findings provide support for the proposal that Schwann cells produce NGF and question the accepted hypothesis that the molecule is produced by smooth muscle fibres as a peripheral maintenance factor for sympathetic and sensory nerves. The results also suggest that two survival factors may be involved in the regulation of sympathetic function.

Identification and quantification of mRNA for nerve growth factor in histological preparations

Hybridization histochemistry has been used to detect mRNA for nerve growth factor (NGF) in histological preparations of mouse salivary glands and rat iris using a 32P-labelled cDNA probe and autoradiography. Label was visible over the tubular cells of the male mouse submaxillary gland but not the sublingual gland. A much lower label density was found over the tubular cells of the female submaxillary gland, whereas sections of liver and pancreas were negative. Quantitative autoradiography allowed the detection of low levels of mRNA for NGF in the rat iris which was elevated by prior culture of the tissue. The results provide direct histological evidence for the presence of specific NGF-mRNA in the mouse submaxillary gland and rat iris, with increased levels following culture.