Cloning of the cDNA for the putative calcium-sensing receptor and its tissue distribution in sea bream (Sparus aurata)

Flanagan, Julia; Bendell, L; Guerreiro, Pedro; Clark, Melody S.; Power, Deborah M.; Canário, Adelino V.M.; Brown, Brian; Ingleton, P. M.

doi:10.1016/s0016-6480(02)00035-7

Cited by 38 publications

(20 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…CaRs have been cloned from osmoregulatory tissues in the sea bream Sparus aurata (9), the dogfish shark Squalus acanthias (35), and the Mozambique tilapia Oreochromis mossambicus (28). CaR expression in the intestine is elevated in SW tilapia, and intracellular CaR signaling involves activation of phospholipase C and mitogen-activated protein kinase cascades (29).…”

Section: Discussionmentioning

confidence: 99%

Identification of intestinal bicarbonate transporters involved in formation of carbonate precipitates to stimulate water absorption in marine teleost fish

Kurita

Nakada

Kato

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

110

146

View full text Add to dashboard Cite

Marine teleost fish precipitate divalent cations as carbonate deposits in the intestine to minimize the potential for excessive Ca2+ entry and to stimulate water absorption by reducing luminal osmotic pressure. This carbonate deposit formation, therefore, helps maintain osmoregulation in the seawater (SW) environment and requires controlled secretion of HCO3(-) to match the amount of Ca2+ entering the intestinal lumen. Despite its physiological importance, the process of HCO3(-) secretion has not been characterized at the molecular level. We analyzed the expression of two families of HCO3(-) transporters, Slc4 and Slc26, in fresh-water- and SW-acclimated euryhaline pufferfish, mefugu (Takifugu obscurus), and obtained the following candidate clones: NBCe1 (an Na+-HCO3(-) cotransporter) and Slc26a6A and Slc26a6B (putative Cl(-)/HCO3(-) exchangers). Heterologous expression in Xenopus oocytes showed that Slc26a6A and Slc26a6B have potent HCO3(-)-transporting activity as electrogenic Cl(-)/nHCO3(-) exchangers, whereas mefugu NBCe1 functions as an electrogenic Na+-nHCO3(-) cotransporter. Expression of NBCe1 and Slc26a6A was highly induced in the intestine in SW and expression of Slc26a6B was high in the intestine in SW and fresh water, suggesting their involvement in HCO3(-) secretion and carbonate precipitate formation. Immunohistochemistry showed staining on the apical (Slc26a6A and Slc26a6B) and basolateral (NBCe1) membranes of the intestinal epithelial cells in SW. We therefore propose a mechanism for HCO3(-) transport across the intestinal epithelial cells of marine fish that includes basolateral HCO3(-) uptake (NBCe1) and apical HCO3(-) secretion (Slc26a6A and Slc26a6B).

show abstract

Section: Discussionmentioning

confidence: 99%

Identification of intestinal bicarbonate transporters involved in formation of carbonate precipitates to stimulate water absorption in marine teleost fish

Kurita

Nakada

Kato

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

110

146

View full text Add to dashboard Cite

show abstract

“…In the pituitary gland, a significant downregulation of casr mRNA was observed after both short-and long-term calcium constraint, indicating that the need for calcium controlled processes had decreased or reflecting a need for desensitisation to Ca 2+ signals. Flanagan et al (Flanagan et al, 2002) located immunostaining for CaSR in cells bordering the W. Abbink and others pn in both the pi and the pars distalis in the sea bream pituitary gland and suggested a possible feedback between nerve axons from hypothalamic nuclei and pituitary factors affected by calcium. This is supported by the localisation of sPTHrP in cells near the pn in this study, thereby possibly controlling the upregulation of pthrp gene expression in the gills.…”

Section: Mrna Expressionmentioning

confidence: 94%

PTHrP regulation and calcium balance in sea bream (Sparus auratusL.) under calcium constraint

Abbink

Bevelander

Hang

et al. 2006

Journal of Experimental Biology

View full text Add to dashboard Cite

SUMMARY Juvenile gilthead sea bream were exposed to diluted seawater (2.5‰salinity; DSW) for 3 h or, in a second experiment, acclimated to DSW and fed a control or calcium-deficient diet for 30 days. Branchial Ca2+influx, drinking rate and plasma calcium levels were assessed. Sea bream plasma parathyroid hormone related protein (sPTHrP) was measured, and mRNAs of pthrp, its main receptor, pth1r, and the calcium-sensing receptor (casr) were quantified in osmoregulatory tissues and the pituitary gland. When calcium is limited in water or diet, sea bream maintain calcium balance; however, both plasma Ca2+ and plasma sPTHrP concentrations were lower when calcium was restricted in both water and diet. Positive correlations between plasma sPTHrP and plasma Ca2+(R2=0.30, N=39, P<0.05), and plasma sPTHrP and body mass of the fish (R2=0.37, N=148, P<0.001) were found. Immunoreactive sPTHrP was demonstrated in pituitary gland pars intermedia cells that border the pars nervosa and co-localises with somatolactin. In the pituitary gland, pthrp, pth1r and casr mRNAs were downregulated after both short-and long-term exposure to DSW. A correlation between pituitary gland pthrp mRNA expression and plasma Ca2+(R2=0.71, N=7, P<0.01) was observed. In gill tissue, pthrp and pth1r mRNAs were significantly upregulated after 30 days exposure to DSW, whereas no effect was found for casr mRNA expression. We conclude that in water of low salinity,declining pituitary gland pthrp mRNA expression accompanied by constant plasma sPTHrP levels points to a reduced sPTHrP turnover and that sPTHrP, through paracrine interaction, is involved in the regulation of branchial calcium handling, independently of endocrine pituitary gland sPTHrP.

show abstract

“…Our observations of vascular endfeet of coronet cell processes and of direct contacts of coronet cells with the basement membrane favor the hypothesis that coronet cells are involved in ion exchanges between blood vessels and CSF and in the homeostasis of the CSF [Jansen and Flight, 1969;Jansen et al, 1981Jansen et al, , 1982see Altner and Zimmermann, 1972]. More recently peptides related to calcium homeostasis such as the parathyroid hormone-related protein and a possible calcium-sensing receptor (CaSR) have been shown in the coronet cells [Ingleton et al, 1995;Devlin et al, 1996;Akino et al, 1998;Flanagan et al, 2002] although their functions in the SV have not yet been clarified. The close relationship of some coronet cell processes with blood vessels, together with their immunoreactivity to an astroglial marker (GFAP), indicates that coronet cells are glial, probably astroglial derivatives.…”

Section: Gfap Immunoreactivity In Shark Coronet Cellsmentioning

confidence: 99%

“…Classical studies indicated that these cells have axons [Dammerman, 1910], although this has not been confirmed by ultrastructural studies [Zimmermann and Altner, 1970]. No neuroactive substances have been shown in coronet cells but immunohistochemical and in situ hybridization studies have shown that these cells contain peptides and receptors related to calcium homeostasis [Ingleton et al, 1995;Devlin et al, 1996;Akino et al, 1998;Flanagan et al, 2002] supporting the hypothesis that coronet cells, as some glial cells, are involved in ion transport [Jansen et al, 1981[Jansen et al, , 1982. Coronet cells of Scyliorhinus and Mustelus showed no immunoreactivity to S-100 protein, a tanycytic glia marker [Chiba et al, 1989;Chiba, 2000], but in a teleost, coronet cells showed immunoreactivity to vimentin, an intermediate filament protein expressed in some glial cells [Arochena et al, 2004].…”

mentioning

confidence: 99%

New Insights on Saccus vasculosus Evolution: A Developmental and Immunohistochemical Study in Elasmobranchs

et al. 2007

View full text Add to dashboard Cite

The saccus vasculosus (SV) is a circumventricular organ of the hypothalamus of many jawed fishes whose functions have not yet been clarified. It is a vascularized neuroepithelium that consists of coronet cells, cerebrospinal fluid-contacting (CSF-c) neurons and supporting cells. To assess the organization, development and evolution of the SV, the expression of glial fibrillary acidic protein (GFAP) and the neuronal markers γ-aminobutyric acid (GABA), glutamic acid decarboxylase (GAD; the GABA synthesizing enzyme), neuropeptide Y (NPY), neurophysin II (NPH), tyrosine hydroxylase (TH; the rate-limiting catecholamine-synthesizing enzyme) and serotonin (5-HT), were investigated by immunohistochemistry in developing and adult sharks. Coronet cells showed GFAP immunoreactivity from embryos at stage 31 to adults, indicating a glial nature. GABAergic CSF-c neurons were evidenced just when the primordium of the SV becomes detectable (at stage 29). Double immunolabeling revealed colocalization of NPY and GAD in these cells. Some CSF-c cells showed TH immunoreactivity in postembryonic stages. Saccofugal GABAergic fibers formed a defined SV tract from the stage 30 and scattered neurosecretory (NPH-immunoreactive) and monoaminergic (5-HT- and TH-immunoreactive) saccopetal fibers were first detected at stages 31 and 32, respectively. The early differentiation of GABAergic neurons and the presence of a conspicuous GABAergic saccofugal system are shared by elasmobranch and teleosts (trout), suggesting that GABA plays a key function in the SV circuitry. Monoaminergic structures have not been reported in the SV of bony fishes, and were probably acquired secondarily in sharks. The existence of saccopetal monoaminergic and neurosecretory fibers reveals reciprocal connections between the SV and hypothalamic structures which have not been previously detected in teleosts.

show abstract

Cloning of the cDNA for the putative calcium-sensing receptor and its tissue distribution in sea bream (Sparus aurata)

Cited by 38 publications

References 28 publications

Identification of intestinal bicarbonate transporters involved in formation of carbonate precipitates to stimulate water absorption in marine teleost fish

Identification of intestinal bicarbonate transporters involved in formation of carbonate precipitates to stimulate water absorption in marine teleost fish

PTHrP regulation and calcium balance in sea bream (Sparus auratusL.) under calcium constraint

New Insights on Saccus vasculosus Evolution: A Developmental and Immunohistochemical Study in Elasmobranchs

Contact Info

Product

Resources

About