Transmission and scanning electron-microscopic observations on tanycytes in the mediobasal hypothalamus and the median eminence of adrenalectomized rats

Jp, Brion; Depierreux, Michel; Couck, A. M.; Flament-Durand, J

doi:10.1007/bf00215708

Cited by 12 publications

(9 citation statements)

References 23 publications

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“…They do not incorporate horseradish peroxidase injected intraventricularly, suggesting that they are intracellular structures (Brion et al 1982). Transmission electron-microscopic studies (Brion et al 1982;Bodoky et al 1979;Amat et al 1999) indicate that these large cisternae are localized within tanycytes. The availability of a specific immunological marker for tanycytes has allowed us, in the present investigation, to demonstrate that many of these vacuoles are, indeed, within basal processes of tanycytes labeled with anti-P85.…”

Section: Discussionmentioning

confidence: 96%

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Antibodies obtained by xenotransplantation of organ-cultured median eminence specifically recognize hypothalamic tanycytes

Blázquez

Guerra

Pastor

et al. 2002

Cell and Tissue Research

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Tanycytes are specialized ependymal cells lining the infundibular recess of the third ventricle of the cerebrum. Early and recent investigations involve tanycytes in the mechanism of gonadotropin-releasing hormone (GnRH) release to the portal blood. The present investigation was performed to obtain a specific immunological marker of tanycytes and to identify the compound(s) responsible for this labeling. After 30 days of organ culture, explants of bovine median eminence formed spherical structures mostly constituted by tanycytes. These tanycyte spheres were xenotransplanted to rats, and the antibodies raised by the host animals against the transplanted living tanycytes were used for immunochemical studies of the bovine and rat median eminence. This antiserum immunoreacted with two compounds of 60 kDa and 85 kDa present in extracts of bovine and rat median eminence. The individual immunoblotting analysis of rat medial basal hypothalami showed a decrease in the amount of the 85-kDa compound in castrated rats as compared to control rats processed at oestrus and dioestrus. The antiserum, labeled as anti-P85, when used for immunostaining of sections throughout the rat central nervous system, immunoreacted specifically with the hypothalamic tanycytes. Within tanycytes, P-85 immunoreactivity was exclusively present in the basal processes. It is suggested that the 85-kDa and 60-kDa compounds correspond to two novel proteins selectively expressed by tanycytes. The possibility that they are secretory proteins involved in GnRH release is discussed. Anti-P85 appears to be the first specific marker of hypothalamic tanycytes.

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Section: Discussionmentioning

confidence: 96%

“…Brion et al 1982). Transmission electron-microscopic analysis clearly showed that these vacuoles are intracellular structures located within dilated portions of processes most likely corresponding to basal processes of tanycytes (Fig.…”

Section: Organ Culture Of Bovine Median Eminencementioning

confidence: 99%

Antibodies obtained by xenotransplantation of organ-cultured median eminence specifically recognize hypothalamic tanycytes

Blázquez

Guerra

Pastor

et al. 2002

Cell and Tissue Research

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“…Wittkowski 48 and Kobayashi et al90 described neuroglial cells in the median eminence characterised by a well-developed Golgi apparatus, numerous mitochondria and abundant lipid droplets (0.5-2 μm) localised in the perikaryon and cell processes. After adrenalectomy and castration, the number of lipid bodies in the median eminence neuroglial cells increases 49,90,134. We have recently revisited the ultrastructure of pituicytes of the median eminence.…”

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confidence: 99%

Tanycytes: A rich morphological history to underpin future molecular and physiological investigations

Rodríguez

Guerra

Peruzzo

et al. 2019

J Neuroendocrinology

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Tanycytes are located at the base of the brain and retain characteristics from their developmental origins, such as radial glial cells, throughout their life span. With transport mechanisms and modulation of tight junction proteins, tanycytes form a bridge connecting the cerebrospinal fluid with the external limiting basement membrane. They also retain the powers of self‐renewal and can differentiate to generate neurones and glia. Similar to radial glia, they are a heterogeneous family with distinct phenotypes. Although the four subtypes so far distinguished display distinct characteristics, further research is likely to reveal new subtypes. In this review, we have re‐visited the work of the pioneers in the field, revealing forgotten work that is waiting to inspire new research with today's cutting‐edge technologies. We have conducted a systematic ultrastructural study of α‐tanycytes that resulted in a wealth of new information, generating numerous questions for future study. We also consider median eminence pituicytes, a closely‐related cell type to tanycytes, and attempt to relate pituicyte fine morphology to molecular and functional mechanism. Our rationale was that future research should be guided by a better understanding of the early pioneering work in the field, which may currently be overlooked when interpreting newer data or designing new investigations.

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“…Further, we suspect that the cisterns that are normally present within the median eminence predispose this region to vacuolation. Tangential evidence for this hypothesis is supported by a study whereby adrenalectomy in adult rats increased the abundance of hypothalamic cisterns (40). Since adrenalectomy causes low serum sodium, this observation is consistent with our findings in the present hyponatremic model.…”

Section: Discussionmentioning

confidence: 98%

Vacuolar Pathology in the Median Eminence of the Hypothalamus After Hyponatremia

Levine¹,

Saltzman²,

Ginsberg³

2011

J Neuropathol Exp Neurol

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The median eminence of the hypothalamus is an important conduit by which neurosecretory hormones from hypothalamic nuclei are delivered to the pars nervosa (neural lobe) of the pituitary en route to the bloodstream. Dilutional hyponatremia was produced in adult rats to determine the effect on the morphology of the median eminence of the hypothalamus. Hyponatremia was caused by reducing electrolyte and organic osmolyte reserves in order to block the excretion of water through delivery of the nephrotoxin mercuric chloride (HgCl2). Histological examination of the brain 1 day following a hyponatremic insult revealed vacuolation within the median eminence of the hypothalamus. No other lesions were found in other parts of the brain following hyponatremia. The hyponatremic lesion consisted of a band of closely packed vacuoles that crossed the floor of the third ventricle. Vacuoles associated with hyponatremia were predominantly in the subependymal, fiber, reticular, and palisade layers of the median eminence. Vacuolation was not observed in the tanycyte layer of the median eminence. This study indicates that the median eminence is a potentially vulnerable site in human hyponatremic conditions that should be evaluated further in relevant animal models.

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Transmission and scanning electron-microscopic observations on tanycytes in the mediobasal hypothalamus and the median eminence of adrenalectomized rats

Cited by 12 publications

References 23 publications

Antibodies obtained by xenotransplantation of organ-cultured median eminence specifically recognize hypothalamic tanycytes

Antibodies obtained by xenotransplantation of organ-cultured median eminence specifically recognize hypothalamic tanycytes

Tanycytes: A rich morphological history to underpin future molecular and physiological investigations

Vacuolar Pathology in the Median Eminence of the Hypothalamus After Hyponatremia

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