Aqueductal tanycytes in the rabbit brain: A Golgi study

Burnett, Bruce T.; Felten, David L.

doi:10.1002/ar.1092000314

Cited by 20 publications

(10 citation statements)

References 41 publications

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“…With regard to the tanycyte, Tennyson and Pappas (1962) claimed that these cells were only transitional and not present in the adult. This does not agree with the results presented here as abundant numbers of tanycytes were found in the cerebral aqueduct of the adult rabbit, nor does it agree with observations made by Burnett and Felten (1981) in a Golgi study of the adult rabbit cerebral aqueduct.…”

Section: Ependymacontrasting

confidence: 99%

“…A t the present time, there are no reports on the structure of the cerebral aqueduct in any species using scanning electron microscopy. Apart from early descriptions of the ultrastructure of the normal aqueductal ependyma using the transmission electron microscope by Tennyson and Pappas (1962) in the foetal and adult rabbit and by Brightman and Palay (1963) in the adult rat, along with Golgi investigations of the aqueductal tanycyte in the rabbit (Burnett and Felten, 1981), there have been no other attempts to provide an examination of the cerebral aqueduct in any species by light microscopy or by scanning or transmission electron microscopy. The present report is the first to comprehensively examine the ultrastructure of the cerebral aqueduct of the rabbit using scanning and transmission electron microscopy and Golgi impregnation methods.…”

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confidence: 99%

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A scanning and transmission electron microscopic analysis of the cerebral aqueduct in the rabbit

Meller

Dennis

1993

Anat. Rec.

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An examination of the surface of the cerebral aqueduct with the scanning electron microscope revealed that the walls of the cerebral aqueduct were so heavily ciliated that most of the ependymal surface was obscured, yet certain specialized supraependymal structures could be discerned lying on (or embedded within) this matt of cilia. These structures were determined by transmission electron microscopy and Golgi analysis to be either macrophages, supraependymal neurons, dendrites from medial periaqueductal gray neurons, or axons of unknown origin. Some axons, which were found to contain vesicles, appeared to make synaptic contacts with ependymal cells. Using the transmission electron microscope, the ependymal lining was found to consist of two different cell types: normal ependymal cells and tanycytes which have a long tapering basal process that was observed to contact blood vessels or, more rarely, seemed to terminate in relation to neuronal elements. While there have been previous reports on the structure of the third and lateral ventricles in other species, there are limited reports in the rabbit. The present report is not only the first description for the rabbit, but it is the first complete scanning and transmission electron microscopic analysis of the cerebral aqueduct in any species.

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Section: Ependymacontrasting

confidence: 99%

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confidence: 99%

A scanning and transmission electron microscopic analysis of the cerebral aqueduct in the rabbit

Meller

Dennis

1993

Anat. Rec.

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“…In the brainstem of P8 cats, the R2D5-positive palisade embraced most neurons ofthe raphe nuclei, and even in adult cat, a large number of neurons in the dorsal parts of the raphe neuronal system were located within the palisade of the R2D5-positive processes. In Golgi studies of developing and adult rabbit brainstem, Felten and coworkers (12)(13)(14) found that raphe nuclei neurons frequently abutted radial processes oftanycytes (which presumably correspond to R2D5-positive radial processes) lining the floor of the fourth ventricle, and suggested that these tanycytes constitute a communication channel between the cerebrospinal fluid of the fourth ventricle and medullary raphe neurons. However, with the Golgi method, which randomly labels a small number of cells, it is difficult to examine the spatial arrangement of the entire midline radial glial system.…”

Section: Discussionmentioning

confidence: 99%

Monoclonal antibody R2D5 reveals midsagittal radial glial system in postnatally developing and adult brainstem.

Mori¹,

Ikeda²,

Hayaishi³

1990

Proc. Natl. Acad. Sci. U.S.A.

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Radial glial cells and their processes play critical roles in organizing the spatial arrangement of the nervous system in the embryonic brain. It has been thought that following completion of their roles in the embryo, most of the radial glial processes disappear before or shortly after birth. Here we use R2D5, a monoclonal antibody to a soluble cytosolic protein, to demonstrate that a specific system of midsagittal radial glial cells persists in postnatal and adult brain. In the brainstem of postnatally developing and adult rabbits and cats, the R2D5-positive processes of radial glial cells were observed to be arranged in a precisely parallel array at the midsagittal seam. These radial glial processes formed a continuous palisade separating the right and left brainstem. In early postnatal animals, R2D5-positive radial processes were found to reach the pial surface and to cover the entire midsagittal seam of the brainstem. These processes embraced dendrites and somata of neurons in almost all of the midsagittal nuclei, including the raphe nuclei, suggesting that the radial glial cells may interact with the midsagittal groups of neurons. In addition, the palisade of R2D5-positive radial processes formed loose openings for crossing axonal bundles at the midline decussations of fiber tracts. In more mature brains, somata of R2D5-positive radial glial cells that had migrated ventrally were observed within the palisades, and in adult cats, most of the R2D5-positive radial processes were found to have retracted from the ventral parts of the midsagittal seam. The spatial arrangement of R2D5-positive processes suggests that they may have persistent functional roles as an interface between ventricular humoral signals and midsagittal groups of neurons in the postnatally developing brainstem and in the adult brainstem. The structure of the midline glial system suggests also that it plays a role in organizing the spatial arrangement of decussating axons during development.Radial glial cells are process-bearing ependymal cells lining the surface of brain ventricles and the central canal of the spinal cord. These are the first class of glial cells to appear during embryonic development and they are thought to play critical roles in organizing the spatial arrangement of the nervous system (1, 2). In lower vertebrates, for example, radial processes of ependymal cells have been reported to form channels for growing axons during both regeneration and embryonic development and thus have been suggested to display on their surfaces trace pathways that the axons follow toward their destination (3, 4). In the mammalian embryo, ependymal cells project their processes (radial glial fibers) to almost all regions of the brain and are thought to supply pathways guiding the migration of newly generated neurons (1, 5). Most of these mammalian radial glial cells disappear before birth (5) and process-bearing ependymal cells (tanycytes) have been reported to be present only in restricted portions of the adult brain (6).Using an antibod...

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“…This process does not finish for some time after birth, because the persistence of certain foetal signs may also be observed in 2-month-old lambs (perhaps older individuals). It is probably one of the causes of shape variability not only in prenatal but also postnatal ependymal cells, which has led some authors to attempt their typing (Milhouse 1971;Burnett and Felten 1981;Fernández-Llebrez et al 1981;Rajtová 1987).…”

Section: Discussionmentioning

confidence: 99%

The Foetal Ependyma of Cerebral Ventricles in Sheep and Goat. The Third Cerebral Ventricle in the Light and Scanning Electron Microscope

Rajtová¹

1999

Acta Vet. Brno

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Rajtová V.: The Foetal Ependyma of Cerebral Ventricles in Sheep and Goat. The Third Cerebral Ventricle in the Light and Scanning Electron Microscope. Acta Vet. Brno 68, 1999: 241-245.The study of the ependyma of the third cerebral ventricle in 35 sheep foetuses and 16 goat foetuses using a histological method, Golgi-Cox impregnation and scanning electron microscope has revealed that the 3-4 layered ependyma (between days 40 and 50 of development) changes through the pseudo-layered (up to day 130) in the typical one-layered ependyma (not long before the birth). The external morphology of foetal ependymal cells is very variable. This is related to the change of their location and gradual alteration. Remains from the foetal period can still be seen in 2-month-old lambs in the region of the upper third cerebral ventricle. In the region of the third cerebral ventricle between days 50 and 130 a co-arctation is formed, where many foetal ependymal cells are mitotically active. The surfaces of the apical membranes of proximal processes as well as the bodies of foetal ependymal cells, except for cilia, are covered with microvilli and spherical secretory protrusions.

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Aqueductal tanycytes in the rabbit brain: A Golgi study

Cited by 20 publications

References 41 publications

A scanning and transmission electron microscopic analysis of the cerebral aqueduct in the rabbit

A scanning and transmission electron microscopic analysis of the cerebral aqueduct in the rabbit

Monoclonal antibody R2D5 reveals midsagittal radial glial system in postnatally developing and adult brainstem.

The Foetal Ependyma of Cerebral Ventricles in Sheep and Goat. The Third Cerebral Ventricle in the Light and Scanning Electron Microscope

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