A Rapid Silver Impregnation Method for Nervous Tissue: A Modified Protargol-Peroxide Technic

Loots, G. P.; Loots, J.M.; Brown, John M.; Schoeman, J. L.

doi:10.3109/10520297909112642

Cited by 36 publications

(2 citation statements)

References 5 publications

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“…Silver staining of axonal pnthwuys in the dermis. Loots silver method (Loots et al, 1979) was modified for frozen sections. Pieces ofback skin (approximately 1 cm2) were excised, spread flat on a piece of cork, and plunged into liquid nitrogen-cooled isopentane.…”

Section: Morphological Examinationsmentioning

confidence: 99%

Endogenous NGF and nerve impulses regulate the collateral sprouting of sensory axons in the skin of the adult rat

1992

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We have investigated the co-involvement of endogenous NGF and impulses in the collateral sprouting of cutaneous sensory nerves in adult rats, specifically the A delta-axons involved in mechanonociception and the C-fibers that mediate heat nociception. Their collateral sprouting was measured by the progressive expansion, respectively, of the behaviorally defined "pinch" and "heat" fields into surrounding denervated skin (the light-touch A alpha-fibers do not sprout in adult mammals). The expansions of such "isolated" fields were totally prevented in animals injected daily with anti-NGF serum, but developed normally after treatment was discontinued. Light microscopic and EM examination of the skin confirmed that the effect of the anti-NGF treatment was attributable to its prevention of collateral sprouting. Initiation of treatment would also rapidly halt sprouting already in progress. Finally, intradermal injections of purified NGF protein would not only increase the rate of nociceptive fiber sprouting, but also evoke sprouting de novo within normally innervated skin (again, A alpha-axons were unaffected). We conclude that the collateral sprouting of intact nociceptive nerves following partial denervation of skin is entirely dependent on endogenous NGF. The observed latency of this sprouting was 10-12 d; we estimate, however, that at least 2 d of field expansion is required for its reliable detection. Thus, about 8-10 d are required for NGF levels in the skin to rise to effective levels, and for the neurons to respond and initiate sprouting. From indirect findings, the NGF component of this sprouting latency appears to be about 2 d. In accord with earlier findings, the remaining "initiation time" was reduced by 5-6 d if the neurons were briefly excited, even 2 d prior to the isolation of their fields. Unexpectedly, this phenomenon of "precocious sprouting" requires that endogenous NGF be available; the sprouting latency reverted to normal values when the conditioning impulses were evoked during a 2 d anti-NGF "umbrella." In contrast to the impulse-sensitive neuronal mechanisms involved in the initiation of sprouting, those underlying the sprouting rate were unaffected by nerve activity and were entirely dependent on the level of endogenous NGF. We suggest that interactions like that revealed in these studies between a sprouting agent and impulses that seem to prime the neuron's response to it contribute to plasticity within the nervous system.

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Section: Morphological Examinationsmentioning

confidence: 99%

Endogenous NGF and nerve impulses regulate the collateral sprouting of sensory axons in the skin of the adult rat

1992

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“…Sections were cut at 8 pm, mounted on slides, and dried overnight. The sections were then stained according to the modified protargol-peroxide technique described by Loots et al (1979). Both the goldtoned and silver-enhanced methods were used.…”

Section: Silver Stainmentioning

confidence: 99%

Organization of the olfactory system in the adult zebrafish: Histological, immunohistochemical, and quantitative analysis

Byrd

Brunjes

1995

J of Comparative Neurology

120

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The zebrafish, Danio rerio, is becoming an important model system for developmental studies. We have used a variety of histological techniques to characterize the adult structure of the olfactory system in this teleost to form a base for future developmental work. The olfactory epithelium in this fish contains ciliated and microvillar sensory neurons, microvillar supporting cells, secretory goblet cells, and basal cells, and the adjacent nonsensory epithelium contains ciliated supporting cells. The olfactory bulb is a diffusely organized structure with four laminae: olfactory nerve, glomerular, mixed mitral cell/plexiform, and granule cell layers. These structures and the synapses observed in the olfactory bulb are typical of what is found in other vertebrates. We also examined the distribution of several neurotransmitter markers (tyrosine hydroxylase, neuropeptide Y, dopamine-beta-hydroxylase, and serotonin) in the olfactory bulb. Antibodies to neuropeptide Y, dopamine-beta-hydroxylase, and serotonin labeled fibers in the olfactory bulb and cell bodies in caudal regions of the brain in distributions comparable to other species. Tyrosine hydroxylase immunoreactivity was observed in a set of intrinsic bulb neurons with extensive processes in the glomerular layer. In addition, the structural proteins glial fibrillary acidic protein and vimentin have distributions similar to those in the olfactory bulbs of other animals. Thus, the adult olfactory structures are analogous to the structures in other vertebrate animals in morphology and chemical neuroanatomy. This similarity, along with its numerous advantages for developmental studies, makes the zebrafish a good model for studies of olfaction and forebrain maturation.

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Neuronal changes in the forebrain of mice following penetration by regenerating olfactory axons

Graziadei

1986

J of Comparative Neurology

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Following total, unilateral bulbectomy in neonatal mice, the olfactory sensory axons regrow from a reconstituted population of sensory neurons, cross the lamina cribrosa, and invade the spared forebrain that has leaned forward toward the anteroventral wall of the cranial cavity. The sensory axons invade several regions of the spared forebrain, at times penetrating deeply into the brain parenchyma. These axons terminate in characteristic globose structures resembling the glomeruli of the olfactory bulb. However, they can be distinguished from the latter by the absence of periglomerular cells. These ectopic glomerular structures are formed by the commingling of the olfactory axon terminals and the dendrites of brain neurons that lie in their proximity. Previously we have established that synaptic contacts occur between the sensory axon terminals and the dendrites of the brain neurons. Our present study describes large neurons, resembling mitral cells, that expand their dendrites into the intracerebral glomeruli. These neurons are recognized by virtue of their relatively large diameter, their selective stainability with silver methods, and the unorthodox arrangement of their dendrites in comparison with the neurons of the region. Their appearance is contingent upon the presence of ectopic glomeruli. The possibility is discussed that the large argyrophilic neurons may be derived from developing neuronal elements of the brain.

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A Rapid Silver Impregnation Method for Nervous Tissue: A Modified Protargol-Peroxide Technic

Cited by 36 publications

References 5 publications

Endogenous NGF and nerve impulses regulate the collateral sprouting of sensory axons in the skin of the adult rat

Endogenous NGF and nerve impulses regulate the collateral sprouting of sensory axons in the skin of the adult rat

Organization of the olfactory system in the adult zebrafish: Histological, immunohistochemical, and quantitative analysis

Neuronal changes in the forebrain of mice following penetration by regenerating olfactory axons

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