Functional retinal input stimulates expression of astroglial elements in the suprachiasmatic nucleus of postnatal developing rat

Ikeda, Teru; Iijima, Norio; Munekawa, Katsuhiko; Ishihara, Akihiko; Ibata, Yasuhiko; Tanaka, Masaki

doi:10.1016/s0168-0102(03)00165-2

Cited by 19 publications

(17 citation statements)

References 31 publications

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“…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. In a recent study, Ikeda et al (2003) have described a significant decrease of GFAP-Ir in the SCN of rats kept in DD since birth compared with the controls raised in LD. In that paper, the authors discuss the absence of circadian variation of GFAP-Ir in the rat SCN, referring to the Tamada et al (1998) study mentioned above.…”

Section: Discussionmentioning

confidence: 96%

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: 96%

Circadian variation in GFAP immunoreactivity in the mouse suprachiasmatic nucleus

Santos¹,

Araújo²,

Cunha³

et al. 2005

Biological Rhythm Research

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“…In contrast, at nanomolar concentrations, PACAP has no more effect on ERK phosphorylation and reduces astrocyte proliferation by inhibiting the RhoA GTPase activity . RhoA and PI3-K inactivation are also involved in PACAP-induced astrocyte stellation (Ikeda et al, 2003;Perez et al, 2005).…”

Section: Kip2mentioning

confidence: 99%

Pituitary Adenylate Cyclase-Activating Polypeptide and Its Receptors: 20 Years after the Discovery

et al. 2009

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“…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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Functional retinal input stimulates expression of astroglial elements in the suprachiasmatic nucleus of postnatal developing rat

Cited by 19 publications

References 31 publications

Circadian variation in GFAP immunoreactivity in the mouse suprachiasmatic nucleus

Circadian variation in GFAP immunoreactivity in the mouse suprachiasmatic nucleus

Pituitary Adenylate Cyclase-Activating Polypeptide and Its Receptors: 20 Years after the Discovery

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

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