Molecular biology of major components of chloride cells

Hirose, Shigehisa; Kaneko, Toyoji; Naito, Nobuko; Takei, Yoshiyuki

doi:10.1016/s1096-4959(03)00287-2

Cited by 266 publications

(191 citation statements)

References 275 publications

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“…So far, at least two pathways have been proposed for the apical transport of Na + in fish gill cells (Hirose et al, 2003;Perry et al, 2003;Evans et al, 2005): (1) an apical V-type H + -ATPase electrically linked to Na + absorption via the epithelial Na + channel (ENaC) and (2) an electroneutral exchange of Na + and H + via an apical Na + /H + exchanger (NHE). As the uptake of Na + via passive exchange with H + has been questioned on thermodynamic grounds (Kirschner, 1983;Avella and Bornancin, 1989), most of the latter studies favoured the major role of H + -ATPase in acid-secretion and Na + -uptake mechanisms.…”

Section: H + -Atpase Rich (Hr) Cellsmentioning

confidence: 99%

“…Pleomorphic ionocytes in various species have been identified based on different criteria depending on the study (Hirose et al, 2003;Hwang and Lee, 2007), but generalizing a comprehensive working model of fish ion-regulatory mechanisms by comparing the pleomorphic ionocytes among species would be of physiological and evolutional significance. In the past decade, most studies on pleomorphic ionocytes focused particularly on FW fish, probably because FW environments are more diverse than SW ones in terms of ionic composition, pH, hardness, etc.…”

Section: Comparison Of Ionocytes Between Speciesmentioning

confidence: 99%

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Ion uptake and acid secretion in zebrafish (Danio rerio)

Hwang

2009

Journal of Experimental Biology

169

165

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SummaryTransepithelial transport is one of the major processes involved in the mechanism of homeostasis of body fluids in vertebrates including fish. The current models of ion regulation in fish gill ionocytes have been proposed mainly based on studies in traditional model species like salmon, trout, tilapia, eel and killifish, but the mechanisms are still being debated due to the lack of convincing molecular physiological evidence. Taking advantage of plentiful genetic databases for zebrafish, we studied the molecular/cellular mechanisms of ion regulation in fish skin/gills. In our recently proposed model, there are at least three subtypes of ionocytes in zebrafish skin/gills: Na + -K + -ATPase-rich (NaR), Na + -Cl -cotransporter (NCC) and H + -ATPase-rich (HR) cells. Specific isoforms of transporters and enzymes have been identified as being expressed by these ionocytes: zECaC, zPMCA2 and zNCX1b by NaR cells; zNCC gill form by NCC cells; and zH + -ATPase, zNHE3b, zCA2-like a and zCA15a by HR cells. Serial molecular physiological experiments demonstrated the distinct roles of these ionocytes in the transport of various ions: HR, NaR and NCC cells are respectively responsible for acid secretion/Na + uptake, Ca 2+ uptake and Cl -uptake. The expression, regulation and function of transporters in HR and NaR cells are much better understood than those in NCC cells. The basolateral transport pathways in HR and NCC cells are still unclear, and the driving forces for the operations of apical NHE and NCC are another unresolved issue. Studies on zebrafish skin/gill ionocytes are providing new insights into fish ion-regulatory mechanisms, but the zebrafish model cannot simply be applied to other species because of species differences and a lack of sufficient molecular physiological evidence in other species.

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Section: H + -Atpase Rich (Hr) Cellsmentioning

confidence: 99%

Section: Comparison Of Ionocytes Between Speciesmentioning

confidence: 99%

Ion uptake and acid secretion in zebrafish (Danio rerio)

Hwang

2009

Journal of Experimental Biology

169

165

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“…In both environments, mitochondrion-rich cells (MRCs) and their adjoining accessory and pavement cells are fundamental to compensatory ion transport for which the driving force is delivered by the Na C ,K C -atpase and in the FW mode possibly complemented by an apical V-type H C -ATPase (see Hirose et al 2003). The recent discovery of different Na C ,K C -atpase a-1 isoforms in the salmonid teleost gill (a1a, a1b and a1c; Richards et al 2003) has offered new insight into transepithelial ion transport in the gill.…”

Section: Introductionmentioning

confidence: 99%

Distinct hormonal regulation of Na+,K+-atpase genes in the gill of Atlantic salmon (Salmo salar L.)

Tipsmark

Madsen²

2009

Journal of Endocrinology

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It has recently become evident that maintenance of ionic homoeostasis in euryhaline salmonids involves a reciprocal shift in expression of two isoforms of the gill Na+,K+-atpase α-subunit when the surrounding salinity changes. The present study investigated the regulation of this shift between the α1a (freshwater (FW) isoform) and the α1b (seawater (SW) isoform) by cortisol, Gh, prolactin (Prl) and Igf 1. Injection with cortisol into FW salmon increased α1a expression, while Gh had no effect. Conversely, both cortisol and Gh stimulated α1b expression, and a significant synergy was observed. igf1 expression was increased by Gh in both gill and liver, and inhibited by cortisol in the liver. Gill igf1 and gh receptor expression increased in response to cortisol. Injection with Prl into SW salmon compromised their hypo-osmoregulatory performance, selectively reduced the expression of the α1b isoform and decreased enzymatic Na+,K+-atpase activity in the gill. Cortisol and Prl reduced gill and liver igf1 expression, and both hormones stimulated gill igf1 receptor expression. In a short-term experiment with incubation of FW gill cell suspensions, cortisol stimulated α1a and α1b expression, while Igf1 stimulated only α1b. The data elaborate our understanding of Prl and Gh as being antagonists in the control of gill ion regulation, and support a dual role for Gh involving endocrine and paracrine Igf1 action. Gh and Prl may be the decisive stimuli that direct cortisol-aided mitochondrion-rich cell development into either secretory or absorptive types.

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“…While an increase in gill NKA activity was observed in milkfish, killifish, and striped bass [26,31], other fish species including tilapia, eel, and salmon showed an alternative NKA response, namely, an increase in hyperosmotic medium [8,16,18]. This difference appears to be caused by the dependence of H + -ATPase or Na 6).…”

Section: Resultsmentioning

confidence: 99%

“…However, the growth of marine fish at lower salinities seems to be advantageous as many marine fish exhibit better growth and feeding efficiency under conditions of intermediate salinity similar to those of brackish water, i.e., [8][9][10][11][12][13][14][15][16][17][18][19][20] ppt [9,10,14]. This might be due to reduced osmotic stress and disease associated with parasites that prefer higher salinity.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Gene Encoding Isotocin and its Expression in Cinnamon Clownfish, Amphiprion melanopus

Noh¹,

Choi²,

Min³

et al. 2016

Journal of Life Science

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Isotocin (IT), a nonapeptide homolog of oxytocin in mammals, has been suggested to be involved in physiological processes including social behaviors, stress responses, and osmoregulation in teleost fish. To study its structure and function, the gene encoding the IT precursor was cloned from the genomic DNA and brain cDNA of the cinnamon clownfish, Amphiprion melanopus. The IT precursor gene consists of three exons separated by two introns, and encodes an open reading frame of 156 amino acid (aa) residues, comprising a putative signal peptide of 19 aa, a mature IT protein of 9 aa, a proteolytic processing site of 3 aa, and 125 aa of neurophysin. Tissue-specific analysis of the IT precursor transcript indicated its expression in the brain and gonads of A. melanopus. To examine its osmoregulatory effects, the salinity of the seawater (34 ppt) used for rearing A. melanopus was lowered to 15 ppt. Histological analysis of the gills indicated the apparent disappearance of an apical crypt on the surface of the gill lamella of A. melanopus, as pavement cells covered the surface upon acclimation to the lower salinity. The level of NaATPase activity in the gills was increased during the initial stage of acclimation, followed by a decrease to its normal level, suggesting its involvement in osmoregulation and homeostasis. The only slight increase in the level of IT precursor transcript in the A. melanopus brain upon low-salinity acclimation suggested that IT played a minor role, if any, in the process of osmoregulation.

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Molecular biology of major components of chloride cells

Cited by 266 publications

References 275 publications

Ion uptake and acid secretion in zebrafish (Danio rerio)

Ion uptake and acid secretion in zebrafish (Danio rerio)

Distinct hormonal regulation of Na+,K+-atpase genes in the gill of Atlantic salmon (Salmo salar L.)

Investigation of the Gene Encoding Isotocin and its Expression in Cinnamon Clownfish, Amphiprion melanopus

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