1
|
Ghilardi M, Salter MA, Parravicini V, Ferse SCA, Rixen T, Wild C, Birkicht M, Perry CT, Berry A, Wilson RW, Mouillot D, Bejarano S. Temperature, species identity and morphological traits predict carbonate excretion and mineralogy in tropical reef fishes. Nat Commun 2023; 14:985. [PMID: 36813767 PMCID: PMC9947118 DOI: 10.1038/s41467-023-36617-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 02/08/2023] [Indexed: 02/24/2023] Open
Abstract
Anthropogenic pressures are restructuring coral reefs globally. Sound predictions of the expected changes in key reef functions require adequate knowledge of their drivers. Here we investigate the determinants of a poorly-studied yet relevant biogeochemical function sustained by marine bony fishes: the excretion of intestinal carbonates. Compiling carbonate excretion rates and mineralogical composition from 382 individual coral reef fishes (85 species and 35 families), we identify the environmental factors and fish traits that predict them. We find that body mass and relative intestinal length (RIL) are the strongest predictors of carbonate excretion. Larger fishes and those with longer intestines excrete disproportionately less carbonate per unit mass than smaller fishes and those with shorter intestines. The mineralogical composition of excreted carbonates is highly conserved within families, but also controlled by RIL and temperature. These results fundamentally advance our understanding of the role of fishes in inorganic carbon cycling and how this contribution will change as community composition shifts under increasing anthropogenic pressures.
Collapse
Affiliation(s)
- Mattia Ghilardi
- Leibniz Centre for Tropical Marine Research (ZMT), Fahrenheitstraße 6, 28359, Bremen, Germany. .,Department of Marine Ecology, Faculty of Biology and Chemistry, University of Bremen, Leobener Straße UFT, 28359, Bremen, Germany.
| | | | - Valeriano Parravicini
- PSL Université Paris: EPHE-UPVD-CNRS, USR3278 CRIOBE, University of Perpignan, 66860, Perpignan, France.,Institut Universitaire de France, Paris, France
| | - Sebastian C A Ferse
- Leibniz Centre for Tropical Marine Research (ZMT), Fahrenheitstraße 6, 28359, Bremen, Germany.,Department of Marine Ecology, Faculty of Biology and Chemistry, University of Bremen, Leobener Straße UFT, 28359, Bremen, Germany
| | - Tim Rixen
- Leibniz Centre for Tropical Marine Research (ZMT), Fahrenheitstraße 6, 28359, Bremen, Germany
| | - Christian Wild
- Department of Marine Ecology, Faculty of Biology and Chemistry, University of Bremen, Leobener Straße UFT, 28359, Bremen, Germany
| | - Matthias Birkicht
- Leibniz Centre for Tropical Marine Research (ZMT), Fahrenheitstraße 6, 28359, Bremen, Germany
| | - Chris T Perry
- Geography, University of Exeter, Exeter, EX4 4RJ, UK
| | - Alex Berry
- Biosciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Rod W Wilson
- Biosciences, University of Exeter, Exeter, EX4 4QD, UK
| | - David Mouillot
- Institut Universitaire de France, Paris, France.,MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, 34095, Montpellier, France
| | - Sonia Bejarano
- Leibniz Centre for Tropical Marine Research (ZMT), Fahrenheitstraße 6, 28359, Bremen, Germany
| |
Collapse
|
2
|
Wang F, Zhu L, Wei Y, Gao P, Liu Y, Zhou K, Sun Z, Lai Q, Yao Z. Intestinal ion regulation exhibits a daily rhythm in Gymnocypris przewalskii exposed to high saline and alkaline water. Sci Rep 2022; 12:807. [PMID: 35039520 PMCID: PMC8764090 DOI: 10.1038/s41598-021-04472-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 12/22/2021] [Indexed: 11/23/2022] Open
Abstract
Naked carp (Gymnocypris przewalskii), endemic to the saline-alkaline Lake Qinghai, have the capacity to tolerate combinations of high salinity and alkalinity, but migrate to spawn in freshwater rivers each year. In this study, we measured the drinking rate over a 24 h period for naked carp exposed to saline-alkaline lake waters with salinities of 15 (L15) and 17 (L17). We also assessed the daily feed intakes of naked carp exposed to L15 and fresh water (FW). Additionally, we studied the daily expression of acid–base regulation and osmoregulation related genes and proteins in the intestine of naked carp exposed to saline-alkaline lake waters. Our results revealed that the drinking rate at night was significantly higher than in daytime when exposed to either L15 or L17, while feed intakes in daytime were significantly higher than at night. The relative expression of Na+/K+-ATPase α (NKA-α), solute carrier family members 26A6 (SLC26A6) and 4A4 (SLC4A4) in the intestine of naked carp exposed to L17 at night was higher than in daytime. Specifically, NKA-α mRNA expression at 4:00 was 7.22-fold and 5.63-fold higher than that at 10:00 and 16:00, respectively, and the expression at 22:00 was 11.29-fold and 8.80-fold higher than that at 10:00 and 16:00, respectively. Similarly, SLC26A6 mRNA expression was greatest at 22:00, exceeding that observed at 4:00, 10:00 and 16:00 by 3.59, 4.44 and 11.14-fold, respectively. Finally, the expression of NKA-α and SLC26A6 protein at the single cell level was also higher at night than during the day, which was 1.65-fold and 1.37-fold higher at 22:00 respectively compared to 16:00. Overall, the present findings revealed that naked carp drinks at night and feeds during the day, demonstrating that intestinal ion regulation exhibits a daily rhythm when exposed to high saline and alkaline lake water.
Collapse
Affiliation(s)
- Fei Wang
- Engineering Research Center for Saline-alkaline Fisheries, Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China.,National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Lin Zhu
- Engineering Research Center for Saline-alkaline Fisheries, Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China
| | - Yuxing Wei
- Engineering Research Center for Saline-alkaline Fisheries, Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China.,National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Pengcheng Gao
- Engineering Research Center for Saline-alkaline Fisheries, Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China
| | - Yimeng Liu
- Engineering Research Center for Saline-alkaline Fisheries, Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China
| | - Kai Zhou
- Engineering Research Center for Saline-alkaline Fisheries, Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China
| | - Zhen Sun
- Engineering Research Center for Saline-alkaline Fisheries, Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China
| | - Qifang Lai
- Engineering Research Center for Saline-alkaline Fisheries, Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China.
| | - Zongli Yao
- Engineering Research Center for Saline-alkaline Fisheries, Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China.
| |
Collapse
|
3
|
Kandalski PK, Zaleski T, Forgati M, Baduy F, Eugênio DS, Machado C, de Souza MRDP, Piechnik CA, Fávaro LF, Donatti L. Effect of long-term thermal challenge on the Antarctic notothenioid Notothenia rossii. FISH PHYSIOLOGY AND BIOCHEMISTRY 2019; 45:1445-1461. [PMID: 31172345 DOI: 10.1007/s10695-019-00660-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 05/20/2019] [Indexed: 06/09/2023]
Abstract
The thermal stability of the Antarctic Ocean raises questions concerning the metabolic plasticity of Antarctic notothenioids to changes in the environmental temperature. In this study, Notothenia rossii survived 90 days at 8 °C, and their condition factor level was maintained. However, their hepatosomatic (0.29×) index decreased, indicating a decrease in nutrient storage as a result of changes in the energy demands to support survival. At 8 °C, the plasma calcium, magnesium, cholesterol, and triglyceride concentrations decreased, whereas the glucose (1.91×) and albumin (1.26×) concentrations increased. The main energy substrate of the fish changed from lipids to glucose due to a marked increase in lactate dehydrogenase activity, as demonstrated by an increase in anaerobic metabolism. Moreover, malate dehydrogenase activity increased in all tissues, suggesting that fish acclimated at 8 °C exhibit enhanced gluconeogenesis. The aerobic demand increased only in the liver due to an increase (2.23×) in citrate synthase activity. Decreases in the activities of superoxide dismutase, catalase, and glutathione-S-transferase to levels that are most likely sufficient at 8 °C were observed, establishing a new physiological activity range for antioxidant defense. Our findings indicate that N. rossii has some compensatory mechanisms that enabled its long-term survival at 8 °C.
Collapse
Affiliation(s)
| | - Tania Zaleski
- Adaptive Biology Laboratory, Department of Cell Biology, Federal University of Parana, Curitiba, Paraná, Brazil
| | - Mariana Forgati
- Adaptive Biology Laboratory, Department of Cell Biology, Federal University of Parana, Curitiba, Paraná, Brazil
| | - Flávia Baduy
- Adaptive Biology Laboratory, Department of Cell Biology, Federal University of Parana, Curitiba, Paraná, Brazil
- Comparative Endocrinology and Integrative Biology, CCMar, University of Algarve, Faro, Portugal
| | - Danilo Santos Eugênio
- Adaptive Biology Laboratory, Department of Cell Biology, Federal University of Parana, Curitiba, Paraná, Brazil
| | - Cintia Machado
- Adaptive Biology Laboratory, Department of Cell Biology, Federal University of Parana, Curitiba, Paraná, Brazil
| | | | - Cláudio Adriano Piechnik
- Adaptive Biology Laboratory, Department of Cell Biology, Federal University of Parana, Curitiba, Paraná, Brazil
| | - Luís Fernando Fávaro
- Fish Reproduction and Community Laboratory, Department of Cell Biology, Federal University of Parana, Curitiba, Paraná, Brazil
| | - Lucélia Donatti
- Adaptive Biology Laboratory, Department of Cell Biology, Federal University of Parana, Curitiba, Paraná, Brazil.
| |
Collapse
|
4
|
Alves A, Gregório SF, Egger RC, Fuentes J. Molecular and functional regionalization of bicarbonate secretion cascade in the intestine of the European sea bass (Dicentrarchus labrax). Comp Biochem Physiol A Mol Integr Physiol 2019; 233:53-64. [PMID: 30946979 DOI: 10.1016/j.cbpa.2019.03.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/20/2019] [Accepted: 03/25/2019] [Indexed: 10/27/2022]
Abstract
In marine fish the intestinal HCO3- secretion is the key mechanism to enable luminal aggregate formation and water absorption. Using the sea bass (Dicentrarchus labrax), the present study aimed at establishing the functional and molecular organization of different sections of the intestine concerning bicarbonate secretion and Cl- movements. The proximal intestinal regions presented similar HCO3- secretion rates, while differences were detected in the molecular expression of the transporters involved and on regional HCO3- concentrations. The anterior region presented significantly higher Na+/K+-ATPase activity, Cl- transepithelial transport and basolateral slc4a4, apical slc26a6 and slc26a3 expression levels. In the mid intestine, the total HCO3- content was significantly increased in the fluid as in the carbonate aggregates. In the rectum no HCO3- secretion was observed and was characterized by the diminished HCO3- total content, residual molecular expression of slc4a4, slc26a6 and slc26a3, higher H+-ATPase activity and expression, suggesting the existence of a different bicarbonate handling mechanism. The possible regulation of HCO3- secretion by extracellular HCO3- and increased intracellular cAMP levels were also investigated. cAMP did not affect HCO3- secretion, although Cl- secretion was enhanced by cftr. HCO3- secretion rise due to the HCO3- basolateral increment showed that at resting levels slc4a4 was not a limiting step for secretion. The transcellular/intracellular dependence of apical HCO3- secretion differed between the proximal regions. In conclusion, intestinal HCO3- secretion has a functional region-dependent organization that was not reflected by the anterior-posterior regionalization on HCO3- secretion and expression profiles of chloride/water absorption related genes.
Collapse
Affiliation(s)
- Alexandra Alves
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Sílvia F Gregório
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Renata C Egger
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Juan Fuentes
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| |
Collapse
|
5
|
Brauner CJ, Shartau RB, Damsgaard C, Esbaugh AJ, Wilson RW, Grosell M. Acid-base physiology and CO2 homeostasis: Regulation and compensation in response to elevated environmental CO2. FISH PHYSIOLOGY 2019. [DOI: 10.1016/bs.fp.2019.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
6
|
Interrogation of the Gulf toadfish intestinal proteome response to hypersalinity exposure provides insights into osmoregulatory mechanisms and regulation of carbonate mineral precipitation. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2018; 27:66-76. [DOI: 10.1016/j.cbd.2018.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 06/11/2018] [Accepted: 06/18/2018] [Indexed: 12/26/2022]
|
7
|
Gregório SF, Fuentes J. Regulation of Bicarbonate Secretion in Marine Fish Intestine by the Calcium-Sensing Receptor. Int J Mol Sci 2018; 19:E1072. [PMID: 29617283 PMCID: PMC5979614 DOI: 10.3390/ijms19041072] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/26/2018] [Accepted: 04/01/2018] [Indexed: 12/29/2022] Open
Abstract
In marine fish, high epithelial intestinal HCO₃− secretion generates luminal carbonate precipitates of divalent cations that play a key role in water and ion homeostasis. The present study was designed to expose the putative role for calcium and the calcium-sensing receptor (CaSR) in the regulation of HCO₃− secretion in the intestine of the sea bream (Sparus aurata L.). Effects on the expression of the CaSR in the intestine were evaluated by qPCR and an increase was observed in the anterior intestine in fed fish compared with unfed fish and with different regions of intestine. CaSR expression reflected intestinal fluid calcium concentration. In addition, anterior intestine tissue was mounted in Ussing chambers to test the putative regulation of HCO₃− secretion in vitro using the anterior intestine. HCO₃− secretion was sensitive to varying calcium levels in luminal saline and to calcimimetic compounds known to activate/block the CaSR i.e., R 568 and NPS-2143. Subsequent experiments were performed in intestinal sacs to measure water absorption and the sensitivity of water absorption to varying luminal levels of calcium and calcimimetics were exposed as well. It appears, that CaSR mediates HCO₃− secretion and water absorption in marine fish as shown by responsiveness to calcium levels and calcimimetic compounds.
Collapse
Affiliation(s)
- Sílvia F Gregório
- Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| | - Juan Fuentes
- Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| |
Collapse
|
8
|
Ruiz-Jarabo I, Gregório SF, Gaetano P, Trischitta F, Fuentes J. High rates of intestinal bicarbonate secretion in seawater tilapia (Oreochromis mossambicus). Comp Biochem Physiol A Mol Integr Physiol 2017; 207:57-64. [PMID: 28238831 DOI: 10.1016/j.cbpa.2017.02.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 02/13/2017] [Accepted: 02/20/2017] [Indexed: 01/07/2023]
Abstract
Osmoregulation in fish is a complex process that requires the orchestrated cooperation of many tissues. In fish facing hyperosmotic environments, the intestinal absorption of some monovalent ions and the secretion of bicarbonate are key processes to favor water absorption. In the present study, we showed that bicarbonate levels in the intestinal fluid are several fold higher in seawater than in freshwater acclimated tilapia (Oreochromis mossambicus). In addition, we analyzed gene expression of the main molecular mechanisms involved in HCO3- movements i.e. slc26a6, slc26a3, slc4a4 and v-type H-ATPase sub C in the intestine of tilapia acclimated to both seawater and freshwater. Our results show an anterior/posterior functional regionalization of the intestine in tilapia in terms of expression patterns, which is affected by environmental salinity mostly in the anterior and mid intestine. Analysis of bicarbonate secretion using pH-Stat in tissues mounted in Ussing chambers reveals high rates of bicarbonate secretion in tilapia acclimated to seawater from anterior intestine to rectum ranging between ~900 and ~1700nmolHCO3-cm-2h-1. However, a relationship between the expression of slc26a6, slc26a3, slc4a4 and the rate of bicarbonate secretion seems to be compromised in the rectum. In this region, the low expression of the bicarbonate transporters could not explain the high bicarbonate secretion rates here described. However, we postulate that the elevated v-type H-ATPase mRNA expression in the rectum could be involved in this process.
Collapse
Affiliation(s)
- I Ruiz-Jarabo
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - S F Gregório
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - P Gaetano
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Messina, Italy
| | - F Trischitta
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Messina, Italy
| | - J Fuentes
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| |
Collapse
|
9
|
Di- and tripeptide transport in vertebrates: the contribution of teleost fish models. J Comp Physiol B 2016; 187:395-462. [PMID: 27803975 DOI: 10.1007/s00360-016-1044-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/12/2016] [Accepted: 10/20/2016] [Indexed: 02/06/2023]
Abstract
Solute Carrier 15 (SLC15) family, alias H+-coupled oligopeptide cotransporter family, is a group of membrane transporters known for their role in the cellular uptake of di- and tripeptides (di/tripeptides) and peptide-like molecules. Of its members, SLC15A1 (PEPT1) chiefly mediates intestinal absorption of luminal di/tripeptides from dietary protein digestion, while SLC15A2 (PEPT2) mainly allows renal tubular reabsorption of di/tripeptides from ultrafiltration, SLC15A3 (PHT2) and SLC15A4 (PHT1) possibly interact with di/tripeptides and histidine in certain immune cells, and SLC15A5 has unknown function. Our understanding of this family in vertebrates has steadily increased, also due to the surge of genomic-to-functional information from 'non-conventional' animal models, livestock, poultry, and aquaculture fish species. Here, we review the literature on the SLC15 transporters in teleost fish with emphasis on SLC15A1 (PEPT1), one of the solute carriers better studied amongst teleost fish because of its relevance in animal nutrition. We report on the operativity of the transporter, the molecular diversity, and multiplicity of structural-functional solutions of the teleost fish orthologs with respect to higher vertebrates, its relevance at the intersection of the alimentary and osmoregulative functions of the gut, its response under various physiological states and dietary solicitations, and its possible involvement in examples of total body plasticity, such as growth and compensatory growth. By a comparative approach, we also review the few studies in teleost fish on SLC15A2 (PEPT2), SLC15A4 (PHT1), and SLC15A3 (PHT2). By representing the contribution of teleost fish to the knowledge of the physiology of di/tripeptide transport and transporters, we aim to fill the gap between higher and lower vertebrates.
Collapse
|
10
|
Cheng SX. Calcium-sensing receptor: A new target for therapy of diarrhea. World J Gastroenterol 2016; 22:2711-2724. [PMID: 26973410 PMCID: PMC4777994 DOI: 10.3748/wjg.v22.i9.2711] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 11/18/2015] [Accepted: 12/08/2015] [Indexed: 02/06/2023] Open
Abstract
Management of acute diarrhea remains a global challenge, particularly in resource-limiting countries. Oral rehydration solution (ORS), a passive rehydrating therapy developed approximately 40 years ago, remains the mainstay treatment. Although ORS is effective for hydration, since it does not inhibit enterotoxin-mediated excessive secretion, reduced absorption and compromised barrier function - the primary mechanisms of diarrhea, ORS does not offer a rapid relief of diarrhea symptom. There are a few alternative therapies available, yet the use of these drugs is limited by their expense, lack of availability and/or safety concerns. Novel anti-diarrheal therapeutic approaches, particularly those simple affordable therapies, are needed. This article explores intestinal calcium-sensing receptor (CaSR), a newly uncovered target for therapy of diarrhea. Unlike others, targeting this host antidiarrheal receptor system appears “all-inclusive”: it is anti-secretory, pro-absorptive, anti-motility, and anti-inflammatory. Thus, activating CaSR reverses changes of both secretory and inflammatory diarrheas. Considering its unique property of using simple nutrients such as calcium, polyamines, and certain amino acids/oligopeptides as activators, it is possible that through targeting of CaSR with a combination of specific nutrients, novel oral rehydrating solutions that are inexpensive and practical to use in all countries may be developed.
Collapse
|
11
|
Rodrigues E, Feijó-Oliveira M, Suda CNK, Vani GS, Donatti L, Rodrigues E, Lavrado HP. Metabolic responses of the Antarctic fishes Notothenia rossii and Notothenia coriiceps to sewage pollution. FISH PHYSIOLOGY AND BIOCHEMISTRY 2015; 41:1205-20. [PMID: 26031510 DOI: 10.1007/s10695-015-0080-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 05/21/2015] [Indexed: 05/20/2023]
Abstract
The present study aimed to assess the sewage effects of the Brazilian Antarctic Station Comandante Ferraz, Admiralty Bay, King George Island, on the hepatic metabolism (energetic, antioxidant, and arginase levels) and levels of plasma constituents of two Antarctic fish species Notothenia rossii and N. coriiceps. The bioassays were conducted under controlled temperature (0 °C) and salinity (35 psu), exposing the fish for 96 h, to sewage effluent diluted in seawater to 0.5 % (v/v). Liver homogenates were tested for the specific activities of the enzymes glucose-6-phosphatase (G6Pase), glycogen phosphorylase (GPase), hexokinase, citrate synthase, lactate dehydrogenase, malate dehydrogenase, glucose-6-phosphate dehydrogenase, superoxide dismutase, glutathione reductase, catalase, and arginase. Plasma levels of glucose, triacylglycerides, cholesterol, total protein, albumin, chloride, magnesium, calcium, and inorganic phosphate were also determined. In N. rossii, the decrease in citrate synthase and the increase in G6Pase and GPase suggested that the sewage effluent activated glycogenolysis and hepatic gluconeogenesis, whereas is N. coriiceps, only G6Pase levels were increased. In N. rossii, sewage effluent induced hypertriglyceridemia without modulating glucose plasma levels, in contrast to N. coriiceps, which developed hypoglycemia without elevating plasma triglyceride levels. The decrease in glutathione reductase levels in N. coriiceps and in superoxide dismutase and catalase in N. rossii suggest that these two species are susceptible to oxidative stress stemming from the production of reactive oxygen species. An increase in magnesium in N. rossii and a decrease in N. coriiceps showed that sewage effluent compromised the control of plasma levels of this cation. Although phylogenetically close, both species of Antarctic fish exhibited different metabolic responses to the sewage effluent, with N. coriiceps showing greater susceptibility to the toxic effects of the pollutants. The present study suggests that the biochemical responses of these two species are potential indicators of metabolic changes caused by sewage effluents.
Collapse
Affiliation(s)
- Edson Rodrigues
- Institute of Basic Bioscience, University of Taubaté, Av. Tiradentes, 500 - Centro, Taubaté, 12.030-180, SP, Brazil.
| | - Mariana Feijó-Oliveira
- Institute of Basic Bioscience, University of Taubaté, Av. Tiradentes, 500 - Centro, Taubaté, 12.030-180, SP, Brazil
| | - Cecília Nohome Kawagoe Suda
- Institute of Basic Bioscience, University of Taubaté, Av. Tiradentes, 500 - Centro, Taubaté, 12.030-180, SP, Brazil
| | - Gannabathula Sree Vani
- Institute of Basic Bioscience, University of Taubaté, Av. Tiradentes, 500 - Centro, Taubaté, 12.030-180, SP, Brazil
| | - Lucélia Donatti
- Departamento of Cell Biology, Federal University of Paraná, Centro Politécnico s/No, Curitiba, 81.530-130, PR, Brazil
| | - Edson Rodrigues
- Institute of Basic Bioscience, University of Taubaté, Av. Tiradentes, 500 - Centro, Taubaté, 12.030-180, SP, Brazil.
| | - Helena Passeri Lavrado
- Departamento of Marine Biology, Federal University of Rio de Janeiro, 373 - CCS - Bloco A - sala 89, Rio de Janeiro, 21.941-902, RJ, Brazil
| |
Collapse
|
12
|
Cooper CA, Regan MD, Brauner CJ, De Bastos ESR, Wilson RW. Osmoregulatory bicarbonate secretion exploits H(+)-sensitive haemoglobins to autoregulate intestinal O2 delivery in euryhaline teleosts. J Comp Physiol B 2014; 184:865-76. [PMID: 25160040 PMCID: PMC4171588 DOI: 10.1007/s00360-014-0844-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 04/01/2014] [Accepted: 04/11/2014] [Indexed: 11/30/2022]
Abstract
Marine teleost fish secrete bicarbonate (HCO3 (-)) into the intestine to aid osmoregulation and limit Ca(2+) uptake by carbonate precipitation. Intestinal HCO3 (-) secretion is associated with an equimolar transport of protons (H(+)) into the blood, both being proportional to environmental salinity. We hypothesized that the H(+)-sensitive haemoglobin (Hb) system of seawater teleosts could be exploited via the Bohr and/or Root effects (reduced Hb-O2 affinity and/or capacity with decreasing pH) to improve O2 delivery to intestinal cells during high metabolic demand associated with osmoregulation. To test this, we characterized H(+) equilibria and gas exchange properties of European flounder (Platichthys flesus) haemoglobin and constructed a model incorporating these values, intestinal blood flow rates and arterial-venous acidification at three different environmental salinities (33, 60 and 90). The model suggested red blood cell pH (pHi) during passage through intestinal capillaries could be reduced by 0.14-0.33 units (depending on external salinity) which is sufficient to activate the Bohr effect (Bohr coefficient of -0.63), and perhaps even the Root effect, and enhance tissue O2 delivery by up to 42 % without changing blood flow. In vivo measurements of intestinal venous blood pH were not possible in flounder but were in seawater-acclimated rainbow trout which confirmed a blood acidification of no less than 0.2 units (equivalent to -0.12 for pHi). When using trout-specific values for the model variables, predicted values were consistent with measured in vivo values, further supporting the model. Thus this system is an elegant example of autoregulation: as the need for costly osmoregulatory processes (including HCO3 (-) secretion) increases at higher environmental salinity, so does the enhancement of O2 delivery to the intestine via a localized acidosis and the Bohr (and possibly Root) effect.
Collapse
Affiliation(s)
- C. A. Cooper
- Department of Chemistry, Wilfrid Laurier University, 75 University Ave. West, Waterloo, ON N2L 3C5 Canada
| | - M. D. Regan
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC Canada
| | - C. J. Brauner
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC Canada
| | - E. S. R. De Bastos
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Exeter, Devon EX4 4QD UK
| | - R. W. Wilson
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Exeter, Devon EX4 4QD UK
| |
Collapse
|
13
|
Larsen EH, Deaton LE, Onken H, O'Donnell M, Grosell M, Dantzler WH, Weihrauch D. Osmoregulation and Excretion. Compr Physiol 2014; 4:405-573. [DOI: 10.1002/cphy.c130004] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
14
|
Rodrigues E, Feijó-Oliveira M, Vani GS, Suda CNK, Carvalho CS, Donatti L, Lavrado HP, Rodrigues E. Interaction of warm acclimation, low salinity, and trophic fluoride on plasmatic constituents of the Antarctic fish Notothenia rossii Richardson, 1844. FISH PHYSIOLOGY AND BIOCHEMISTRY 2013; 39:1591-1601. [PMID: 23748964 DOI: 10.1007/s10695-013-9811-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 05/24/2013] [Indexed: 06/02/2023]
Abstract
The adaptive evolution of the Notothenia rossii occurred under the selective pressure of stable and low temperatures. It is an opportunistic feeder of Antarctic krill and the fluoride in the krill carapace is apparently not toxic. We investigated the interactive effect of fluoride, elevated temperatures, and low salinity on the plasmatic constituents of this Antarctic fish. The experiments were conducted at the Brazilian Antarctic Station Comandante Ferraz (EACF), located on King George Island. The Antarctic fish N. rossii was acclimatized to eight thermo-saline-trophic conditions, combining two temperatures (0 and 4 °C), two salinities (35 and 20), and two trophic conditions (with/without fluoride) for an 11-day period. Trophic fluoride was not able to alter the plasmatic levels of glucose, cholesterol, plasmatic protein, Cl⁻, Mg²⁺, Ca²⁺, and inorganic phosphate, but induced an acute elevation of triglycerides at 0 °C and salinity of 35. At low salinity, hyperglycemia, hypertriglyceridemia, and hypocalcemia were observed. The thermo-saline interaction at 4 °C was able to minimize the effects of fluoride and low salinity on the plasmatic constituents levels.
Collapse
Affiliation(s)
- E Rodrigues
- Department of Cell Biology, Federal University of Paraná, Centro Politécnico s/No, Curitiba, PR, 81530-130, Brazil
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Biogenic fish-gut calcium carbonate is a stable amorphous phase in the gilt-head seabream, Sparus aurata. Sci Rep 2013; 3:1700. [PMID: 23609008 PMCID: PMC3632881 DOI: 10.1038/srep01700] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 04/08/2013] [Indexed: 11/08/2022] Open
Abstract
The main source of calcium carbonate (CaCO₃) in the ocean comes from the shells of calcifying planktonic organisms, but substantial amounts of CaCO₃ are also produced in fish intestines. The precipitation of CaCO₃ assists fish in intestinal water absorption and aids in whole body Ca²⁺ homeostasis. Here we report that the product formed in the intestinal lumen of the gilt-head seabream, Sparus aurata, is an amorphous calcium carbonate (ACC) phase. With FTIR spectroscopy and SEM imaging, our study shows that the fish-derived carbonates from S. aurata are maintained as a stable amorphous phase throughout the intestinal tract. Moreover, intestinal deposits contained up to 54 mol% Mg²⁺, the highest concentration yet reported in biogenic ACC. Mg is most likely responsible for stabilizing this inherently unstable mineral. The fish carbonates also displayed initial rapid dissolution when exposed to seawater, exhibiting a significant increase in carbonate concentration.
Collapse
|
16
|
Gregório SF, Carvalho ESM, Encarnação S, Wilson JM, Power DM, Canário AVM, Fuentes J. Adaptation to different salinities exposes functional specialization in the intestine of the sea bream (Sparus aurata L.). ACTA ACUST UNITED AC 2012; 216:470-9. [PMID: 23038737 DOI: 10.1242/jeb.073742] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The processing of intestinal fluid, in addition to a high drinking rate, is essential for osmoregulation in marine fish. This study analyzed the long-term response of the sea bream (Sparus aurata L.) to relevant changes of external salinity (12, 35 and 55 p.p.t.), focusing on the anterior intestine and in the less-often studied rectum. Intestinal water absorption, epithelial HCO(3)(-) secretion and gene expression of the main molecular mechanisms (SLC26a6, SLC26a3, SLC4a4, atp6v1b, CFTR, NKCC1 and NKCC2) involved in Cl(-) and HCO(3)(-) movements were examined. The anion transporters SLC26a6 and SLC26a3 are expressed severalfold higher in the anterior intestine, while the expression of Atp6v1b (V-type H(+)-ATPase β-subunit) is severalfold higher in the rectum. Prolonged exposure to altered external salinity was without effect on water absorption but was associated with concomitant changes in intestinal fluid content, epithelial HCO(3)(-) secretion and salinity-dependent expression of SLC26a6, SLC26a3 and SLC4a4 in the anterior intestine. However, the most striking response to external salinity was obtained in the rectum, where a 4- to 5-fold increase in water absorption was paralleled by a 2- to 3-fold increase in HCO(3)(-) secretion in response to a salinity of 55 p.p.t. In addition, the rectum of high salinity-acclimated fish shows a sustained (and enhanced) secretory current (I(sc)), identified in vitro in Ussing chambers and confirmed by the higher expression of CFTR and NKCC1 and by immunohistochemical protein localization. Taken together, the present results suggest a functional anterior-posterior specialization with regard to intestinal fluid processing and subsequently to salinity adaptation of the sea bream. The rectum becomes more active at higher salinities and functions as the final controller of intestinal function in osmoregulation.
Collapse
Affiliation(s)
- Sílvia F Gregório
- Centre of Marine Sciences (CCMar), CIMAR - Laboratório Associado, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | | | | | | | | | | | | |
Collapse
|
17
|
Heuer RM, Esbaugh AJ, Grosell M. Ocean Acidification Leads to Counterproductive Intestinal Base Loss in the Gulf Toadfish (Opsanus beta). Physiol Biochem Zool 2012; 85:450-9. [DOI: 10.1086/667617] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
18
|
Becker AG, Gonçalves JF, Burns MDM, Vieira JP, Radünz Neto J, Baldisserotto B. Ion levels in the gastrointestinal tract content of freshwater and marine-estuarine teleosts. FISH PHYSIOLOGY AND BIOCHEMISTRY 2012; 38:1001-1017. [PMID: 22160632 DOI: 10.1007/s10695-011-9585-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 12/01/2011] [Indexed: 05/31/2023]
Abstract
This study investigated the relationship between ion levels (Na⁺, Cl⁻, K⁺, Ca²⁺, and Mg²⁺) in the fluid phase and total chyme of the contents of the gastrointestinal tract segments of freshwater and marine-estuarine teleosts collected in different salinities (0-34 ppt) in estuarine and freshwater portions of the São Gonçalo channel, southern Brazil. In addition, the relative contribution of feeding and osmoregulation to the ionic content of each portion of the gastrointestinal tract of fishes collected in different ambient salinities was analyzed. There was no relationship between salinity and ion levels in the fluid phase and total chyme of the segments of the gastrointestinal tract when considering all species together. However, there was a significant positive relationship between salinity and ion levels in the fluid phase and total chyme of two fish species (Micropogonias furnieri and Genidens barbus) collected in three or more different salinities. In most species, ion levels in the fluid phase and total chyme changed throughout the gastrointestinal tract, suggesting absorption, but the ionoregulatory mechanisms of the gastrointestinal tract seem to vary according to species.
Collapse
Affiliation(s)
- Alexssandro G Becker
- Departamento de Fisiologia e Farmacologia, Universidade Federal de Santa Maria, Santa Maria, RS, 97105-900, Brazil
- Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Jamile F Gonçalves
- Departamento de Fisiologia e Farmacologia, Universidade Federal de Santa Maria, Santa Maria, RS, 97105-900, Brazil
| | - Marcelo D M Burns
- Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, RS, 96201-900, Brazil
| | - João Paes Vieira
- Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, RS, 96201-900, Brazil
| | - João Radünz Neto
- Departamento de Zootecnia, Universidade Federal de Santa Maria, Santa Maria, RS, 97105-900, Brazil
- Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Bernardo Baldisserotto
- Departamento de Fisiologia e Farmacologia, Universidade Federal de Santa Maria, Santa Maria, RS, 97105-900, Brazil.
- Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
| |
Collapse
|
19
|
Carvalho ESM, Gregório SF, Power DM, Canário AVM, Fuentes J. Water absorption and bicarbonate secretion in the intestine of the sea bream are regulated by transmembrane and soluble adenylyl cyclase stimulation. J Comp Physiol B 2012; 182:1069-80. [PMID: 22752677 DOI: 10.1007/s00360-012-0685-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 06/04/2012] [Accepted: 06/09/2012] [Indexed: 10/28/2022]
Abstract
In the marine fish intestine luminal, HCO₃⁻ can remove divalent ions (calcium and magnesium) by precipitation in the form of carbonate aggregates. The process of epithelial HCO₃⁻ secretion is under endocrine control, therefore, in this study we aimed to characterize the involvement of transmembrane (tmACs) and soluble (sACs) adenylyl cyclases on the regulation of bicarbonate secretion (BCS) and water absorption in the intestine of the sea bream (Sparus aurata). We observed that all sections of sea bream intestine are able to secrete bicarbonate as measured by pH-Stat in Ussing chambers. In addition, gut sac preparations reveal net water absorption in all segments of the intestine, with significantly higher absorption rates in the anterior intestine that in the rectum. BCS and water absorption are positively correlated in all regions of the sea bream intestinal tract. Furthermore, stimulation of tmACs (10 μM FK + 500 μM IBMX) causes a significant decrease in BCS, bulk water absorption and short circuit current (Isc) in a region dependent manner. In turn, stimulation of sACs with elevated HCO₃⁻ results in a significant increase in BCS, and bulk water absorption in the anterior intestine, an action completely reversed by the sAC inhibitor KH7 (200 μM). Overall, the results reveal a functional relationship between BCS and water absorption in marine fish intestine and modulation by tmACs and sAC. In light of the present observations, it is hypothesized that the endocrine effects on intestinal BCS and water absorption mediated by tmACs are locally and reciprocally modulated by the action of sACs in the fish enterocyte, thus fine-tuning the process of carbonate aggregate production in the intestinal lumen.
Collapse
Affiliation(s)
- Edison S M Carvalho
- Centre of Marine Sciences (CCMar), CIMAR-Laboratório Associado, Universidade do Algarve, Faro, Portugal
| | | | | | | | | |
Collapse
|
20
|
Al-Jandal NJ, Whittamore JM, Santos EM, Wilson RW. The influence of 17β-estradiol on intestinal calcium carbonate precipitation and osmoregulation in seawater-acclimated rainbow trout (Oncorhynchus mykiss). ACTA ACUST UNITED AC 2011; 214:2791-8. [PMID: 21795578 DOI: 10.1242/jeb.054296] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The intestine of marine teleosts produces carbonate precipitates from ingested calcium as part of their osmoregulatory strategy in seawater. The potential for estrogens to control the production of intestinal calcium carbonate and so influence osmoregulation was investigated in seawater-acclimated rainbow trout following intraperitoneal implantation of 17β-estradiol (E2) at two doses (0.1 and 10 μg E2 g(-1)). Levels of plasma vitellogenin provided an indicator of estrogenic effect, increasing significantly by three and four orders of magnitude at the low and high doses, respectively. Plasma osmolality and muscle water content were unaffected, whereas E2-treated fish maintained lower plasma [Na(+)] and [Cl(-)]. Plasma [Ca(2+)] and [Mg(2+)] and muscle [Ca(2+)] increased with vitellogenin induction, whereas the intestinal excretion of calcium carbonate was reduced. This suggests that elevated levels of circulating E2 may enhance Ca(2+) uptake via the gut and simultaneously reduce CaCO(3) formation, which normally limits intestinal availability of Ca(2+). Increasing E2 caused an elevation of [Na(+)] and [Cl(-)] and a reduction of [HCO(3(-))] in intestinal fluid. We speculate that E2 may influence a number of intestinal ion transport processes that ultimately may influence water absorption: (1) reduced NaCl cotransport, (2) reduced Cl(-) uptake via Cl(-)/HCO(3(-)) exchange and (3) reduced precipitation of Ca(2+) and Mg(2+) carbonates. Despite these effects on intestinal ion and water transport, overall osmoregulatory status was not compromised in E2-treated fish, suggesting the possibility of compensation by other organs.
Collapse
Affiliation(s)
- Noura J Al-Jandal
- Biosciences, College of Life and Environmental Sciences, Hatherly Laboratories, University of Exeter, Exeter EX4 4PS, UK
| | | | | | | |
Collapse
|
21
|
Guffey S, Esbaugh A, Grosell M. Regulation of apical H⁺-ATPase activity and intestinal HCO₃⁻ secretion in marine fish osmoregulation. Am J Physiol Regul Integr Comp Physiol 2011; 301:R1682-91. [PMID: 21865541 DOI: 10.1152/ajpregu.00059.2011] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The absorption of Cl(-) and water from ingested seawater in the marine fish intestine is accomplished partly through Cl(-)/HCO(3)(-) exchange. Recently, a H(+) pump (vacuolar-type H(+)-ATPase) was found to secrete acid into the intestinal lumen, and it may serve to titrate luminal HCO(3)(-) and facilitate further Cl(-)/HCO(3)(-) exchange, especially in the posterior intestine, where adverse concentration gradients could limit Cl(-)/HCO(3)(-) exchange. The H(+) pump is expressed in all intestinal segments and in gill tissue of gulf toadfish (Opsanus beta) maintained in natural seawater. After acute transfer of toadfish to 60 ppt salinity, H(+) pump expression increased 20-fold in the posterior intestine. In agreement with these observations was a fourfold-increased H(+)-ATPase activity in the posterior intestine of animals acclimated to 60 ppt salinity. Interestingly, Na(+)-K(+)-ATPase activity was elevated in the anterior intestine and gill, but not in the posterior intestine. Apical acid secretion by isolated intestinal tissue mounted in Ussing chambers fitted with pH-stat titration systems increased after acclimation to hypersalinity in the anterior and posterior intestine, titrating >20% of secreted bicarbonate. In addition, net base secretion increased in hypersalinity-acclimated fish and was ∼70% dependent on serosal HCO(3)(-). Protein localization by immunohistochemistry confirmed the presence of the vacuolar-type H(+)-ATPase in the apical region of intestinal enterocytes. These results show that the H(+) pump, especially in the posterior intestine, plays an important role in hypersaline osmoregulation and that it likely has significant effects on HCO(3)(-) accumulation in the intestinal lumen and, therefore, the continued absorption of Cl(-) and water.
Collapse
Affiliation(s)
- S Guffey
- Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Miami, Florida 33149, USA.
| | | | | |
Collapse
|
22
|
A comparison of osmoregulatory responses in plasma and tissues of rainbow trout (Oncorhynchus mykiss) following acute salinity challenges. Comp Biochem Physiol A Mol Integr Physiol 2011; 159:175-81. [DOI: 10.1016/j.cbpa.2011.02.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 02/17/2011] [Accepted: 02/17/2011] [Indexed: 11/23/2022]
|
23
|
Carbonate precipitates and bicarbonate secretion in the intestine of sea bass, Dicentrarchus labrax. J Comp Physiol B 2010; 181:517-25. [PMID: 21152925 DOI: 10.1007/s00360-010-0538-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 11/08/2010] [Accepted: 11/10/2010] [Indexed: 10/18/2022]
Abstract
The aim of this paper was to study the chemical composition of the precipitates found in the intestine of Dicentrarchus labrax and the source of HCO(3)(-) secreted into the intestinal lumen. The chemical analysis was performed by employing the potentiometric double titration method and by means of an electron microscope coupled with a spectrometer and X-ray powder diffraction. The results obtained suggest the presence of very insoluble intestinal precipitates, presumably formed by a mixture of CaCO(3) and MgCO(3), with a higher quantity of the former with respect to the latter. HCO(3)(-) secretion rate was investigated with the aid of the pH stat method in isolated tissues mounted in Ussing chamber, where the transepithelial electrical parameters were also measured. When the serosal surface of the intestinal mucosa was bathed in HCO(3)(-)-Ringer bubbled with 1% CO(2) in O(2) while the serosal surface was bathed in HCO(3)(-) free Ringer solution bubbled with pure O(2), bicarbonate secretion proceeded at an almost stable rate of 0.9 ± 0.05 μeq cm(-2) h(-1) for about 3 h while I(sc) maintained a constant value of 38 ± 1.5 μA cm(-2). The carbonic anhydrase inhibitor ethoxyzolamide elicited a progressive reduction of HCO(3)(-) secretion that was about 75% of the initial value after 80 min. When serosal HCO(3)(-)-CO(2) saline was substituted with Hepes-O(2) saline base secretion progressively declined reaching a value of about 20% of the initial value. It was also strongly inhibited when Na(+) was substituted with the impermeant cation choline and when either DIDS or ouabain were added to the basolateral side. These results suggest that most of the bicarbonate secreted is of extracellular source and is probably transported across the basolateral membrane by both Na(+) independent mechanism and Na(+) dependent transporter, presumably a NaHCO(3) cotransport.
Collapse
|
24
|
Cooper CA, Whittamore JM, Wilson RW. Ca2+-driven intestinal HCO(3)(-) secretion and CaCO3 precipitation in the European flounder in vivo: influences on acid-base regulation and blood gas transport. Am J Physiol Regul Integr Comp Physiol 2010; 298:R870-6. [PMID: 20130227 PMCID: PMC2853387 DOI: 10.1152/ajpregu.00513.2009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Accepted: 01/28/2010] [Indexed: 11/22/2022]
Abstract
Marine teleost fish continuously ingest seawater to prevent dehydration and their intestines absorb fluid by mechanisms linked to three separate driving forces: 1) cotransport of NaCl from the gut fluid; 2) bicarbonate (HCO(3)(-)) secretion and Cl(-) absorption via Cl(-)/HCO(3)(-) exchange fueled by metabolic CO(2); and 3) alkaline precipitation of Ca(2+) as insoluble CaCO(3), which aids H(2)O absorption). The latter two processes involve high rates of epithelial HCO(3)(-) secretion stimulated by intestinal Ca(2+) and can drive a major portion of water absorption. At higher salinities and ambient Ca(2+) concentrations the osmoregulatory role of intestinal HCO(3)(-) secretion is amplified, but this has repercussions for other physiological processes, in particular, respiratory gas transport (as it is fueled by metabolic CO(2)) and acid-base regulation (as intestinal cells must export H(+) into the blood to balance apical HCO(3)(-) secretion). The flounder intestine was perfused in vivo with salines containing 10, 40, or 90 mM Ca(2+). Increasing the luminal Ca(2+) concentration caused a large elevation in intestinal HCO(3)(-) production and excretion. Additionally, blood pH decreased (-0.13 pH units) and plasma partial pressure of CO(2) (Pco(2)) levels were elevated (+1.16 mmHg) at the highest Ca perfusate level after 3 days of perfusion. Increasing the perfusate [Ca(2+)] also produced proportional increases in net acid excretion via the gills. When the net intestinal flux of all ions across the intestine was calculated, there was a greater absorption of anions than cations. This missing cation flux was assumed to be protons, which vary with an almost 1:1 relationship with net acid excretion via the gill. This study illustrates the intimate link between intestinal HCO(3)(-) production and osmoregulation with acid-base balance and respiratory gas exchange and the specific controlling role of ingested Ca(2+) independent of any other ion or overall osmolality in marine teleost fish.
Collapse
|