Expression of aquaporin 1 and aquaporin 4 water channels in rat choroid plexus

Speake, Tracey; Freeman, Lyle J.; Brown, Peter de Nully

doi:10.1016/s0005-2736(02)00658-2

Cited by 122 publications

(94 citation statements)

References 30 publications

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“…The mRNA expression profile of AQPs in the ovine CP showed 20 times higher expression of AQP1 compared to all isoforms of AQP4. AQP1 was found to be located almost exclusively in the apical membrane of the CP epithelium, which is in agreement with earlier studies that were conducted on rat CPs (Nielsen et al 1993;Speake et al 2003). This localization directly indicates the involvement of AQP1 in the transport of water through the apical membrane of the CP and, therefore, the involvement of AQP1 in CSF production (Owler et al 2010).…”

Section: Discussionsupporting

confidence: 89%

“…According to Nielsen et al (1993) these bands may correspond with glycosylated and unglycosylated forms of AQP1, respectively. The localization of AQP4 in the ovine CP, which can be characterized as diffuse in the cytoplasm of epithelial cells, is in line with the findings of Speake et al (2003) and Nazari et al (2015). It has been demonstrated that rat AQP4 has six cDNA isoforms which are differentially expressed in the kidney and brain (Moe et al 2008).…”

Section: Discussionsupporting

confidence: 82%

“…AQP1 is abundant on the apical (CSF-facing) surface of rat CPs from the fourth and lateral ventricles (Nielsen et al 1993;Speake et al 2003), therefore during the CSF secretion it plays a major role in mediating water transport across the apical membrane (Oshio et al 2005). The mRNA for AQP4 was initially detected in rat CPs from lateral ventricles, using the hybridization in situ method (Venero et al 1999), thereafter also AQP4 protein was detected as diffusely distributed throughout the epithelial cells of rat CPs from the fourth and lateral ventricles (Speake et al 2003;Nazari et al 2015). It has been demonstrated that in rats the expression of AQP4 protein in astrocytes and AQP1 protein in spinal cord may be modulated by melatonin (Kaur et al 2006;Nesic et al 2008).…”

Section: Doi: 1017221/6/2017-cjasmentioning

confidence: 99%

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Effect of melatonin from slow-release implants on aquaporins (AQP1 and AQP4) in the ovine choroid plexus

Szczepkowska¹,

Skowroński²,

Kowalewska³

et al. 2018

CZECH J ANIM SCI

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Szczepkowska A., Skowroński M.T., Kowalewska M., Milewski S., Skipor J. (2018): Effect of melatonin from slow-release implants on aquaporins (AQP1 and AQP4) in the ovine choroid plexus. Czech J. Anim. Sci., 63, 32-42.Aquaporins (AQPs) play important role in the cerebrospinal fluid (CSF) secretion and AQP1 and AQP4 are localized in the choroid plexus (CP), which is the main place of CSF production. In ewes, seasonally breeding animals, the turnover rate (TOR) of CSF is photoperiodically modulated and melatonin, a biochemical signal about changing photoperiod, is used to advance the onset of the breeding season by mimicking the stimulatory effect of short days (SD). This study evaluates the effect of melatonin implantation during long days (LD) on AQPs expression in the ovine CP. Studies were performed on ovariectomized, estradiol implanted ewes treated with placebo (n = 6) or with melatonin (n = 6) during LD. Ewes were sacrificed 40 days after melatonin/ placebo implantation and CPs from the lateral/third brain ventricles were collected for Real-time and Western blot analyses. Additionally, for immunohistochemical analysis, CP samples were collected from ewes (n = 3) sacrificed during LD. We demonstrated an apical membrane localization of AQP1 and a diffused distribution of AQP4 in the epithelial cells of CP. The mRNA expression of AQP1 was 20 times higher than the expression of all AQP4 isoforms, and among them AQP4 isoforms containing exon 2 constituted approximately 38%. The melatonin implantation significantly (P < 0.05) increased the mRNA expression of AQP1 and AQP4 and the protein level of AQP4 isoforms (33 and 28 kDa). For AQP1 we observed a significant (P < 0.05) decrease of glycosylated (33 kDa) and a significant (P < 0.05) increase of unglycosylated (23 kDa) predominant protein form. Therefore it can be suggested that at least AQP1, which is involved in CSF production and has been demonstrated to be modulated by melatonin implantation, is linked with the photoperiodic modulation of the CSF production in ewes.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 82%

Section: Doi: 1017221/6/2017-cjasmentioning

confidence: 99%

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Effect of melatonin from slow-release implants on aquaporins (AQP1 and AQP4) in the ovine choroid plexus

Szczepkowska¹,

Skowroński²,

Kowalewska³

et al. 2018

CZECH J ANIM SCI

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“…The third reason why the choroid plexuses are considered to the main site of formation should be the fact that the observations mentioned so far were accompanied by a significant number of concurrent studies that pointed to CSF formation by the choroid plexuses (Dandy, 1919;de Rougemont et al, 1960;Pollay et al, 1972;Weed, 1914;Welch, 1963) , and the secretory character of the choroid plexuses was confirmed by the application of the molecular biological methods during the past two decades (Brown et al, 2004;Johanson, 2008;Kanaka et al, 2001;Li et al, 2002;Oshio et al, 2005;Praetorius et al, 2004;Speake et al, 2003;Watts et al, 1991;Zlokovic et al, 1993).…”

Section: Criticism Of the Classic Hypothesis Of Cerebrospinal Fluid Fmentioning

confidence: 97%

“…The secretory character of choroid plexuses that involves pumps, cotransporters and antiporters, ion channels and aquaporins has been confirmed during the past 15 years by the application of molecular biological methods (Brown et al, 2004;Johanson, 2008;Kanaka et al, 2001;Li et al, 2002;Oshio et al, 2005;Praetorius et al, 2004;Speake et al, 2003;Watts et al, 1991;Zlokovic et al, 1993).…”

Section: The Site and The Way Of Cerebrospinal Fluid Formationmentioning

confidence: 98%

The formation of cerebrospinal fluid: Nearly a hundred years of interpretations and misinterpretations

Orešković

Klarica

2010

Brain Research Reviews

289

274

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Hypoxia‐induced astrocytic reaction and increased vascular permeability in the rat cerebellum

Kaur

Sivakumar

Zhang

et al. 2006

Glia

154

137

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Hypoxia is an important factor linked to induction of vascular leakage and formation of brain edema. In this connection, astrocytes associated closely with the blood vessels are deemed to be involved. This study investigated the response of astrocytes to hypoxia in the adult rat cerebellum, and along with this, the integrity of the blood-brain barrier (BBB) was assessed using fluorescent and electron dense tracers. In rats subjected to hypoxia, mRNA and protein expression of hypoxia inducible factor-1alpha (HIF-1alpha), vascular endothelial growth factor (VEGF), glial fibrillary acidic protein (GFAP), and aquaporin-4 (AQ4) was significantly increased. VEGF and AQ4 immunoreactive cells were identified as astrocytes by double immunofluorescence labeling. Increased VEGF tissue concentration and astrocytic swelling as observed in hypoxic rats were reduced after melatonin administration. Following intraperitoneal or intravenous injection of rhodamine isothiocyanate (RhIC) or horseradish peroxidase (HRP), leakage of both tracers was observed in hypoxic rats but not in the controls indicating that functional integrity of BBB is compromised in hypoxia/reoxygenation. Enhanced gene and protein expression of VEGF may contribute to increased permeability of blood vessels. AQ4, a water transporting protein, is upregulated in astrocytes in hypoxia suggesting the cells are involved in edema formation. To this end, melatonin may be beneficial in reducing edema as it reduced VEGF concentration and, hence, vascular permeability.

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Expression of aquaporin 1 and aquaporin 4 water channels in rat choroid plexus

Cited by 122 publications

References 30 publications

Effect of melatonin from slow-release implants on aquaporins (AQP1 and AQP4) in the ovine choroid plexus

Effect of melatonin from slow-release implants on aquaporins (AQP1 and AQP4) in the ovine choroid plexus

The formation of cerebrospinal fluid: Nearly a hundred years of interpretations and misinterpretations

Hypoxia‐induced astrocytic reaction and increased vascular permeability in the rat cerebellum

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