Ultrastructure of spinal efferents to the lateral reticular nucleus: An EM study using anterograde transport of WGA‐HRP complex

Westman, Jan; Danckwardt-Lillieström, Niklas; Dietrichs, Espen; Svensson, Bo; Walberg, Fred

doi:10.1002/cne.902460303

Cited by 15 publications

(3 citation statements)

References 67 publications

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“…the central nervous system. Recent work by one of the authors (Marfurt, unpublished data; see also Crutcher and Marfurt, 1988) has shown that most of the loss in sensitivity that accompanies the use of Procedure 3 may be prevented simply by substituting acetate buffer (also at pH 6,0) for phosphate buffer in all incubation and rinse procedures (Schonitzer and Hollander, 1981;Westman et al;. Thus, with additional experimentation it may be possible to bring about even further improvements in the AM stabilization procedure beyond those reported here.…”

Section: Discussionmentioning

confidence: 99%

Stabilization of tetramethylbenzidine (TMB) reaction product at the electron microscopic level by ammonium molybdate

Marfurt

Turner

Adams

1988

Journal of Neuroscience Methods

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The ability to use the tetramethylbenzidine (TMB) method for studying neuronal connections at the electron microscopic level is often difficult because the conditions of osmification and dehydration used in processing the tissue may result in significant loss and/or decreased electron density of the reaction product. In the present study, we report that stabilization of TMB reaction product with 5% ammonium molybdate (AM) prior to osmificating the tissue results in the formation of TMB-AM crystals that are many times more electron dense and resistant to ethanol extraction than non-stabilized TMB crystals. The nature of the chemical interaction that underlies the stabilization of TMB by AM is uncertain, but it may involve the formation of an insoluble salt between molybdic ions and the TMB polymer. The use of this simple procedure increases the sensitivity of the TMB procedure at the electron microscopic level and may be used to label neuronal pathways in the peripheral and central nervous systems with equal success.

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Section: Discussionmentioning

confidence: 99%

Stabilization of tetramethylbenzidine (TMB) reaction product at the electron microscopic level by ammonium molybdate

Marfurt

Turner

Adams

1988

Journal of Neuroscience Methods

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“…The lateral reticular nucleus (LRN) is one of the main precerebellar nuclei (see data and references in Ito, 1984). It receives afferent connections from the spinal cord (cat: Brodal, 1949;Morin et al, 1966;Kunzle, 1973;Clendenin et al, 1974a, b, c;Mizuno et al, 1975a ;Corvaja et al, 1977a;Hrycyshyn and Flumerfelt, 1981b, c;Westman et al, 1986;opossum: Martin et al, 1977;rat: Flumerfelt et al, 1982a, b;Menetrey et al, 1983;Shokunbi et al, 1985) and from various supraspinal centres such as the cerebral cortex, the red nucleus, the nuclei medialis and interpositalis of the cerebellum (man: Kuypers, 1958c; monkey: Kuypers, 1958b;Batton et al, 1977;cat: Walberg, 1958a, b;Kuypers, 1958a;Hinman and Carpenter, 1959;Walberg and Pompeiano, 1960;Courville, 1966;Brodal et al, 1967;Edwards, 1972;Kitai et al, 1974;Kunzle and Wiesendanger, 1974;Mizuno et al, 1975a;Corvaja et al, 1977a;Hrycyshyn and Flumerfelt, 1981a, b;Qvist et al, 1984;rabbit: Mizuno et al, 1973;opossum: Martin et al, 1977;rat: Shokunbi et al, 1986). Afferent terminals from the various afferent contingents have been found in partly overlapping regions of the LRN in both cats (Qvist, 1989) and rats (Rajakumar et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

The Projections of the Lateral Reticular Nucleus to the Deep Cerebellar Nuclei. An Experimental Analysis in the Rat

Parenti

Cicirata

Pantò

et al. 1996

Eur J of Neuroscience

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The projections of the lateral reticular nucleus (LRN) to the cerebellar nuclei were studied using the retrograde axonal transport of tetramethyl rhodamine dextran amine (10% solution in 0.01 M neutral phosphate buffer) in 19 adult Wistar strain rats. The cerebellar nuclei receive topographically organized projections from the LRN. The projections are bilateral with an ipsilateral predominance and they are symmetrical. The contralateral component is progressively larger for projections to the nuclei interpositalis, to the nucleus lateralis and to the nucleus medialis. The projections to the various cerebellar nuclei arise from rostrocaudally oriented columns of neurons located in different (partly overlapping) areas of the magnocellular division of the LRN. The nucleus lateralis receives terminals from the dorsomedial area (mainly from the rostral level of the LRN), the nuclei interpositalis from the dorsolateral area (mainly from the central level) and the nucleus medialis from the intermedioventral area (mainly from the caudal level). Afferent fibres from the small subtrigeminal division were traced to the three cerebellar nuclei and from the parvocellular division to the nuclei interpositalis and medialis. The density of the projections from the LRN to the nuclei interpositalis increases progressively with the shift of the terminal field from the rostrolateral to the caudomedial part of the nucleus. The projections to the nucleus lateralis reach principally the dorsolateral hump, whereas only a few neurons project to the other divisions (parvo- and magnocellular). The projections to the various regions of the nucleus medialis show different densities. The highest density was found for projections to the caudal part, in particular to the dorsolateral protuberance and to the ventrolateral area of the middle division. Conversely, a low density of projections was found for the other areas of the middle division. The regions of the magnocellular division of the LRN which project to the nuclei lateralis (and are thus related to the cerebral cortex), interpositalis (related to the red nucleus) and medialis (related to the spinal cord) also receive afferent terminals from the cerebral cortex, the red nucleus and the spinal cord respectively, in addition to various afferent inputs. Thus, each of these areas is apparently concerned with integrating some spinal and supraspinal information in reverberating circuits.

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“…Strict adherence to Carson and Mesulam's original procedure (1982; see also Sakumoto et al, 1980, and Sturmer et al, 198 l), which involves reacting the tissue in TMB at pH 3.3 and osmification at pH 6.0 at 45°C resulted, in our hands, in good preservation of TMB crystals but unacceptable loss of ultrastructural detail. Alternatively, we have been able to achieve consistently good results by reacting the tissue in TMB at pH 6.0 in 0.01 M acetate buffer (Schonitzer and Hollander, 198 1;Westman et al, 1986), followed by rapid stabilization of the TMB crystals in a 1% solution of ammonium molybdate (Fujii and Kusama, 1984;Marfurt et al, 1986). The tissue in our study was incubated most often in the TMB medium for approximately 15 min; shorter times led to a significant decrease in the amount of visible reaction product, and longer times resulted in the production of TMB crystals that were so large as to obscure the morphology of the sympathetic sprouts in which they were contained.…”

Section: Methodological Considerationsmentioning

confidence: 99%

Nonregenerative axonal growth within the mature mammalian brain: ultrastructural identification of sympathohippocampal sprouts

Crutcher

Marfurt

1988

J. Neurosci.

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Damage to septohippocampal neurons in the adult rat results in sprouting of sympathetic axons into the denervated hippocampal formation. However, the distribution of sympathohippocampal fibers has only been assessed with light microscopic techniques, and it is not known if the sprouted fibers leave the blood vessels, along which they migrate into the hippocampal formation, to enter the hippocampal neuropil and, if they do, whether they form synaptic contacts with central neurons. Using the tetramethylbenzidine technique to visualize anterogradely transported wheat germ agglutinin-horseradish peroxidase conjugate, we identified sprouted sympathetic fibers in the hippocampal formation at both the light and electron microscopic level in albino rats receiving medial septal lesions. The majority of labeled fibers were observed within the regions immediately above and below the granule cell layer. Although most of the labeled sprouts were observed in association with intraparenchymal blood vessels, where they were usually apposed to the basal lamina, approximately a third of the labeled profiles were present within the neuropil with no obvious vascular relationships. Most of the profiles were identified as unmyelinated axons or vesicle-filled varicosities. Many of the latter structures contained small dense-cored vesicles, but in our sample none of the labeled profiles were observed to form membrane specializations with adjacent structures, and many were partly surrounded by presumed astrocytic processes. These results document the invasion of the CNS by sprouting axons of peripheral origin indicating that axonal elongation from uninjured neurons can occur within the mature mammalian CNS under certain circumstances. In addition, the presence of significant numbers of sympathetic fibers within the hippocampal neuropil indicates that they may be in a strategic position to influence hippocampal function.

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Ultrastructure of spinal efferents to the lateral reticular nucleus: An EM study using anterograde transport of WGA‐HRP complex

Cited by 15 publications

References 67 publications

Stabilization of tetramethylbenzidine (TMB) reaction product at the electron microscopic level by ammonium molybdate

Stabilization of tetramethylbenzidine (TMB) reaction product at the electron microscopic level by ammonium molybdate

The Projections of the Lateral Reticular Nucleus to the Deep Cerebellar Nuclei. An Experimental Analysis in the Rat

Nonregenerative axonal growth within the mature mammalian brain: ultrastructural identification of sympathohippocampal sprouts

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