Development of Astroglial Elements in the Suprachiasmatic Nucleus of the Rat: With Special Reference to the Involvement of the Optic Nerve

Munekawa, Katsuhiko; Tamada, Yoshitaka; Iijima, Norio; Hayashi, Seiji; Ishihara, Akihiko; Inoue, Kenzo; Tanaka, Masaki; Ibata, Yasuhiko

doi:10.1006/exnr.2000.7490

Cited by 28 publications

(35 citation statements)

References 27 publications

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“…In that study, although all of the animals had been sacrificed at the same time, ZT 07, the authors comment they did not observe any significant rhythmicity of GFAP-Ir in the rat SCN based in unpublished data. Later in a developmental GFAP study, Munekawa et al (2000), also based in unpublished data, reported there be no significant circadian rhythmicity in GFAP-Ir under the light-dark condition in the rat SCN at any developmental stage. They attributed the difference between their results and those in hamsters (Lavialle & Servière, 1993) to species differences in the astrocyte function in the SCN, considering that in the rat the GFAP-Ir is found predominantly in the ventrolateral region, while it is present throughout the nucleus in the hamster.…”

Section: Discussionmentioning

confidence: 92%

“…Our results are consistent with this view. It is interesting to note that the glial cells in the SCN mature in parallel with the development of the RHT, according to studies in hamsters (Lavialle & Servière, 1995) and rats (Munekawa et al, 2000). In neuroglial cultures it is also shown that the glial cells regulate the neural activity through the control of the extracellular glutamate levels by NMDA receptors (Parpura et al, 1994).…”

Section: Discussionmentioning

confidence: 95%

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Circadian variation in GFAP immunoreactivity in the mouse suprachiasmatic nucleus

Santos¹,

Araújo²,

Cunha³

et al. 2005

Biological Rhythm Research

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One of the most important functions of biological rhythms is to assure that behavioral and physiological functions are timed optimally in with respect to each other and to the environmental cycles. In mammals, this temporal regulation is driven by a circadian timing system which comprises a circadian pacemaker located in the retinorecipient hypothalamic suprachiasmatic nucleus (SCN), along with a complex network of efferent pathways and target tissues. In this study we investigated the existence of circadian variation in the immunohistochemical expression of glial fibrillary acidic protein (GFAP) in the mouse SCN. We used both entrainment and free-running conditions, and examined GFAP expression at different time points according to 24 hour Zeitgeber time (ZT) and circadian time (CT), respectively. Animals were perfused transcardially, and fixed brain sections containing the SCN were processed for GFAP immunoreactivity. GFAP-Ir was quantified by the percentage measure of pixels method for post-hoc statistical analysis of data. The results indicate the existence of a circadian variation on the expression of the GFAP immunoreactivity in the SCN of the animals of both experimental groups furnishing a contribution to the polemic question that has been raised. Further studies, directed especially to the development of new methods for the measurement of the immunoreactivity of this protein, are essential.

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Section: Discussionmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 95%

Circadian variation in GFAP immunoreactivity in the mouse suprachiasmatic nucleus

Santos¹,

Araújo²,

Cunha³

et al. 2005

Biological Rhythm Research

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“…Astrocyte maturation in mammals is also accompanied by a change in the composition of intermediate filaments. In immature astrocytes, intermediate filaments are composed of Vim (Bennet et al, 1978;Lazarides, 1980Lazarides, , 1982Dahl et al, 1981;Franke et al, 1982;Bignami et al, 1982;Pixley and De Vellis, 1984;Frassoni et al, 2000;Munekawa et al, 2000). As astrocytes mature, Vim tends to be replaced by GFAP (Eng and Bigbee, 1978;Bignami et al, 1980;Levitt and Rakic, 1980;Onteniente et al, 1983).…”

Section: Changes In the Pattern Of Vim And Gfap Immunoreactivity Durimentioning

confidence: 92%

“…In mammals, the expression of Vim in glial cells has been considered as an immature feature; glial cells change to GFAP expression during maturation (Dahl et al, 1981;Frassoni et al, 2000;Munekawa et al, 2000). Previous studies of the glia of teleost brains have not analyzed this question in detail, although disappearance of Vim expression has been observed in zebrafish (Cerdà et al, 1998).…”

Section: Changes In the Pattern Of Vim And Gfap Immunoreactivity Durimentioning

confidence: 94%

Development of vimentin and glial fibrillary acidic protein immunoreactivities in the brain of gray mullet (Chelon labrosus), an advanced teleost

Arochena

Anadón

Díaz-Regueira

2004

J of Comparative Neurology

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Previous studies in teleosts have revealed the presence of the intermediate filaments vimentin (Vim) and glial fibrillary acidic protein (GFAP) in glial cells of the spinal cord and/or some brain regions, but there is no comprehensive study of their distribution and developmental changes in fishes. Here, the distribution of Vim and GFAP immunoreactivities was studied in the brain of larvae, juveniles, and adults of an advanced teleost, the gray mullet (Chelon labrosus). A different sequence of appearance was observed for expression of these proteins: Vim levels decreased with age, whereas GFAP increased. In general, both immunoreactivities were expressed early in perikarya and endfeet of ependymocytes (tanycytes), whereas expression in radial processes appeared later. In large larvae, the similar expression patterns of Vim and GFAP suggest that some of these glial cells contain both proteins. Subependymal radial glia cells were observed mainly in the optic tectum, exhibiting Vim and GFAP immunoreactivity. The only immunoreactive cells with astrocyte-like morphology were observed in the optic chiasm of the adult, and they were positive for both GFAP and Vim. The perivascular processes of glial cells showed a different distribution of Vim and GFAP during development and had a caudorostral sequence of appearance of immunoreactivities similar to that observed for ependymal and radial glia cells. Several circumventricular organs (the organon vasculosum hypothalami, saccus vasculosus, and area postrema) exhibited highly specialized Vim- and/or GFAP-expressing glial cells. The glial cells of the midline septa of several brain regions were also Vim and/or GFAP immunoreactive. In the adult brain, tanycytes retain Vim expression in several brain regions. As in other vertebrates, the regions with Vim-immunoreactive ventricular and midline glia may represent areas with the capability of plasticity and regeneration in adult brain.

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“…In golden hamsters and albino rats, the development of GFAP-immunoreactive astrocytes is stimulated by neuronal terminals of the retinohypothalamic tract (RHT) extending into the SCN (Lavialle and Servière, 1995;Munekawa et al, 2000). Modifications of retinal afferent activity during the light -dark cycle induce astroglial plasticity in the GFAP expression of this nucleus (Lavialle et al, 2001;Ikeda et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

GFAP Expression in Astrocytes of Suprachiasmatic Nucleus and Medial Preoptic Area are Differentially Affected by Malnutrition during Rat Brain Development

Mendonça

Vilela²,

Bittencourt³

et al. 2004

Nutritional Neuroscience

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The aim of the present study was investigate, in young rats, the effects of malnutrition on astrocyte distribution of two hypothalamic regions, the circadian pacemaker suprachiasmatic nucleus (SCN) and the medial preoptic area (MPA). Control rats were born from mothers fed on commercial diet since gestation and malnourished rats from mothers fed on multideficient diet, from the beginning of gestation (GLA group) or from the onset of lactation (LA group). After weaning, pups received ad libitum the same diet as their mothers, and were maintained under a 12/12 h light/dark cycle. The animals were analyzed either at 30-33, or 60-63 days of life. Brain coronal sections (50 microm) were processed to visualize glial fibrillary acidic protein (GFAP) immunoreactivity. Compared to control rats, both malnourished groups of 30 and 60 days exhibited a reduced number of GFAP-immunoreactive astrocytes in the SCN. The total GFAP-immunoreactive area in the SCN of the GLA group differed from the control group at both age ranges analyzed. The GFAP expression as measured by the relative optical density (ROD) exhibited a 50-60% reduction in the MPA in both malnourished groups, compared to controls. The results suggest that malnutrition early in life leads to alterations in gliogenesis or glial cell proliferation in both nuclei, being these alterations greater in the MPA. Compensatory plasticity mechanisms in the GFAP-expression seem to be developed in the astrocyte differentiation process in the SCN, especially when the malnutrition is installed from the lactation.

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Development of Astroglial Elements in the Suprachiasmatic Nucleus of the Rat: With Special Reference to the Involvement of the Optic Nerve

Cited by 28 publications

References 27 publications

Circadian variation in GFAP immunoreactivity in the mouse suprachiasmatic nucleus

Circadian variation in GFAP immunoreactivity in the mouse suprachiasmatic nucleus

Development of vimentin and glial fibrillary acidic protein immunoreactivities in the brain of gray mullet (Chelon labrosus), an advanced teleost

GFAP Expression in Astrocytes of Suprachiasmatic Nucleus and Medial Preoptic Area are Differentially Affected by Malnutrition during Rat Brain Development

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