1
|
Breves JP, Runiewicz ER, Richardson SG, Bradley SE, Hall DJ, McCormick SD. Transcriptional regulation of esophageal, intestinal, and branchial solute transporters by salinity, growth hormone, and cortisol in Atlantic salmon. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024; 341:107-117. [PMID: 38010889 DOI: 10.1002/jez.2766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 11/05/2023] [Accepted: 11/08/2023] [Indexed: 11/29/2023]
Abstract
In marine habitats, Atlantic salmon (Salmo salar) imbibe seawater (SW) to replace body water that is passively lost to the ambient environment. By desalinating consumed SW, the esophagus enables solute-linked water absorption across the intestinal epithelium. The processes underlying esophageal desalination in salmon and their hormonal regulation during smoltification and following SW exposure are unresolved. To address this, we considered whether two Na+ /H+ exchangers (Nhe2 and -3) expressed in the esophagus contribute to the uptake of Na+ from lumenal SW. There were no seasonal changes in esophageal nhe2 or -3 expression during smoltification; however, nhe3 increased following 48 h of SW exposure in May. Esophageal nhe2, -3, and growth hormone receptor b1 were elevated in smolts acclimated to SW for 2.5 weeks. Treatment with cortisol stimulated branchial Na+ /K+ -ATPase (Nka) activity, and Na+ /K+ /2Cl- cotransporter 1 (nkcc1), cystic fibrosis transmembrane regulator 1 (cftr1), and nka-α1b expression. Esophageal nhe2, but not nhe3 expression, was stimulated by cortisol. In anterior intestine, cortisol stimulated nkcc2, cftr2, and nka-α1b. Our findings indicate that salinity stimulates esophageal nhe2 and -3, and that cortisol coordinates the expression of esophageal, intestinal, and branchial solute transporters to support the SW adaptability of Atlantic salmon.
Collapse
Affiliation(s)
- Jason P Breves
- Department of Biology, Skidmore College, Saratoga Springs, New York, USA
| | - Ellie R Runiewicz
- Department of Biology, Skidmore College, Saratoga Springs, New York, USA
| | | | - Serena E Bradley
- Department of Biology, Skidmore College, Saratoga Springs, New York, USA
| | - Daniel J Hall
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, USA
| | - Stephen D McCormick
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, USA
| |
Collapse
|
2
|
Breves JP, McKay IS, Koltenyuk V, Nelson NN, Lema SC, McCormick SD. Na +/HCO 3- cotransporter 1 (nbce1) isoform gene expression during smoltification and seawater acclimation of Atlantic salmon. J Comp Physiol B 2022; 192:577-592. [PMID: 35715660 DOI: 10.1007/s00360-022-01443-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 05/04/2022] [Accepted: 05/20/2022] [Indexed: 10/18/2022]
Abstract
The life history of Atlantic salmon (Salmo salar) includes an initial freshwater phase (parr) that precedes a springtime migration to marine environments as smolts. The development of osmoregulatory systems that will ultimately support the survival of juveniles upon entry into marine habitats is a key aspect of smoltification. While the acquisition of seawater tolerance in all euryhaline species demands the concerted activity of specific ion pumps, transporters, and channels, the contributions of Na+/HCO3- cotransporter 1 (Nbce1) to salinity acclimation remain unresolved. Here, we investigated the branchial and intestinal expression of three Na+/HCO3- cotransporter 1 isoforms, denoted nbce1.1, -1.2a, and -1.2b. Given the proposed role of Nbce1 in supporting the absorption of environmental Na+ by ionocytes, we first hypothesized that expression of a branchial nbce1 transcript (nbce1.2a) would be attenuated in salmon undergoing smoltification and following seawater exposure. In two separate years, we observed spring increases in branchial Na+/K+-ATPase activity, Na+/K+/2Cl- cotransporter 1, and cystic fibrosis transmembrane regulator 1 expression characteristic of smoltification, whereas there were no attendant changes in nbce1.2a expression. Nonetheless, branchial nbce1.2a levels were reduced in parr and smolts within 2 days of seawater exposure. In the intestine, gene transcript abundance for nbce1.1 increased from spring to summer in the anterior intestine, but not in the posterior intestine or pyloric caeca, and nbce1.1 and -1.2b expression in the intestine showed season-dependent transcriptional regulation by seawater exposure. Collectively, our data indicate that tissue-specific modulation of all three nbce1 isoforms underlies adaptive responses to seawater.
Collapse
Affiliation(s)
- Jason P Breves
- Department of Biology, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA.
| | - Ian S McKay
- Department of Biology, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Victor Koltenyuk
- Department of Biology, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Nastasia N Nelson
- Department of Biology, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Sean C Lema
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University, San Luis Obispo, CA, 93407, USA
| | - Stephen D McCormick
- U.S. Geological Survey, Eastern Ecological Science Center, Conte Anadromous Fish Research Laboratory, One Migratory Way, Turners Falls, MA, 01376, USA
| |
Collapse
|
3
|
Shartau RB, Snyman HN, Turcotte L, McCarron P, Bradshaw JC, Johnson SC. Acute microcystin exposure induces reversible histopathological changes in Chinook Salmon (Oncorhynchus tshawytscha) and Atlantic Salmon (Salmo salar). JOURNAL OF FISH DISEASES 2022; 45:729-742. [PMID: 35235682 DOI: 10.1111/jfd.13599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/13/2022] [Accepted: 02/14/2022] [Indexed: 06/14/2023]
Abstract
Atlantic Salmon (Salmo salar) and Chinook Salmon (Oncorhynchus tshawytscha) develop a severe liver disease called net-pen liver disease (NPLD), which is characterized by hepatic lesions that include megalocytosis and loss of gross liver structure. Based on studies where salmonids have been exposed to microcystin (MC) via intraperitoneal injection, NPLD is believed to be caused by MC exposure, a hepatotoxin produced by cyanobacteria. Despite the link between MC and NPLD, it remains uncertain if environmentally relevant MC exposure is responsible for NPLD. To determine if we could produce histopathology consistent with NPLD, we compared the response of Atlantic and Chinook Salmon sub-lethal MC exposure. Salmon were orally gavaged with saline or MC containing algal paste and sampled over 2 weeks post-exposure. Liver lesions appeared by 6 h but were resolved 2-weeks post-exposure; histopathological changes observed in other tissues were not as widespread, nor was their severity as great as those in the liver. There was no evidence for NPLD due to the absence of hepatic megalocytosis. These results indicate that the development of NPLD is not due to acute MC exposure but may be associated with higher MC concentration occurring in food, long-term exposure through drinking of contaminated seawater and/or interactions with other marine toxins.
Collapse
Affiliation(s)
- Ryan B Shartau
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
- Department of Biology, The University of Texas at Tyler, Tyler, Texas, USA
| | - Heindrich N Snyman
- Animal Health Laboratory, University of Guelph, Kemptville, Ontario, Canada
| | - Lenora Turcotte
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
| | - Pearse McCarron
- Biotoxin Metrology, National Research Council Canada, Halifax, Nova Scotia, Canada
| | - Julia C Bradshaw
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
| | - Stewart C Johnson
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
| |
Collapse
|
4
|
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: 0] [Impact Index Per Article: 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
|
5
|
Morgenroth D, McArley T, Ekström A, Gräns A, Axelsson M, Sandblom E. Continuous gastric saline perfusion elicits cardiovascular responses in freshwater rainbow trout (Oncorhynchus mykiss). J Comp Physiol B 2021; 192:95-106. [PMID: 34618204 PMCID: PMC8816557 DOI: 10.1007/s00360-021-01408-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/06/2021] [Accepted: 09/20/2021] [Indexed: 11/30/2022]
Abstract
When in seawater, rainbow trout (Oncorhynchus mykiss) drink to avoid dehydration and display stroke volume (SV) mediated elevations in cardiac output (CO) and an increased proportion of CO is diverted to the gastrointestinal tract as compared to when in freshwater. These cardiovascular alterations are associated with distinct reductions in systemic and gastrointestinal vascular resistance (RSys and RGI, respectively). Although increased gastrointestinal blood flow (GBF) is likely essential for osmoregulation in seawater, the sensory functions and mechanisms driving the vascular resistance changes and other associated cardiovascular changes in euryhaline fishes remain poorly understood. Here, we examined whether internal gastrointestinal mechanisms responsive to osmotic changes mediate the cardiovascular changes typically observed in seawater, by comparing the cardiovascular responses of freshwater-acclimated rainbow trout receiving continuous (for 4 days) gastric perfusion with half-strength seawater (½ SW, ~ 17 ppt) to control fish (i.e., no perfusion). We show that perfusion with ½ SW causes significantly larger increases in CO, SV and GBF, as well as reductions in RSys and RGI, compared with the control, whilst there were no significant differences in blood composition between treatments. Taken together, our data suggest that increased gastrointestinal luminal osmolality is sensed directly in the gut, and at least partly, mediates cardiovascular responses previously observed in SW acclimated rainbow trout. Even though a potential role of mechano-receptor stimulation from gastrointestinal volume loading in eliciting these cardiovascular responses cannot be excluded, our study indicates the presence of internal gastrointestinal milieu-sensing mechanisms that affect cardiovascular responses when environmental salinity changes.
Collapse
Affiliation(s)
- Daniel Morgenroth
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30, Gothenburg, Sweden.
| | - Tristan McArley
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30, Gothenburg, Sweden
| | - Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30, Gothenburg, Sweden
| | - Albin Gräns
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, 532 23, Skara, Sweden
| | - Michael Axelsson
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30, Gothenburg, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30, Gothenburg, Sweden
| |
Collapse
|
6
|
Breves JP, Popp EE, Rothenberg EF, Rosenstein CW, Maffett KM, Guertin RR. Osmoregulatory actions of prolactin in the gastrointestinal tract of fishes. Gen Comp Endocrinol 2020; 298:113589. [PMID: 32827513 DOI: 10.1016/j.ygcen.2020.113589] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/17/2020] [Accepted: 08/14/2020] [Indexed: 02/07/2023]
Abstract
In fishes, prolactin (Prl) signaling underlies the homeostatic regulation of hydromineral balance by controlling essential solute and water transporting functions performed by the gill, gastrointestinal tract, kidney, urinary bladder, and integument. Comparative studies spanning over 60 years have firmly established that Prl promotes physiological activities that enable euryhaline and stenohaline teleosts to reside in freshwater environments; nonetheless, the specific molecular and cellular targets of Prl in ion- and water-transporting tissues are still being resolved. In this short review, we discuss how particular targets of Prl (e.g., ion cotransporters, tight-junction proteins, and ion pumps) confer adaptive functions to the esophagus and intestine. Additionally, in some instances, Prl promotes histological and functional transformations within esophageal and intestinal epithelia by regulating cell proliferation. Collectively, the demonstrated actions of Prl in the gastrointestinal tract of teleosts indicate that Prl operates to promote phenotypes supportive of freshwater acclimation and to inhibit phenotypes associated with seawater acclimation. We conclude our review by underscoring that future investigations are warranted to determine how growth hormone/Prl-family signaling evolved in basal fishes to support the gastrointestinal processes underlying hydromineral balance.
Collapse
Affiliation(s)
- Jason P Breves
- Department of Biology, Skidmore College, 815 N. Broadway, Saratoga Springs, NY 12866, USA.
| | - Emily E Popp
- Department of Biology, Skidmore College, 815 N. Broadway, Saratoga Springs, NY 12866, USA
| | - Eva F Rothenberg
- Department of Biology, Skidmore College, 815 N. Broadway, Saratoga Springs, NY 12866, USA
| | - Clarence W Rosenstein
- Department of Biology, Skidmore College, 815 N. Broadway, Saratoga Springs, NY 12866, USA
| | - Kaitlyn M Maffett
- Department of Biology, Skidmore College, 815 N. Broadway, Saratoga Springs, NY 12866, USA
| | - Rebecca R Guertin
- Department of Biology, Skidmore College, 815 N. Broadway, Saratoga Springs, NY 12866, USA
| |
Collapse
|
7
|
The gaseous gastrointestinal tract of a seawater teleost, the English sole (Parophrys vetulus). Comp Biochem Physiol A Mol Integr Physiol 2020; 247:110743. [PMID: 32531535 DOI: 10.1016/j.cbpa.2020.110743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/04/2020] [Accepted: 06/05/2020] [Indexed: 02/07/2023]
Abstract
There has been considerable recent progress in understanding the respiratory physiology of the gastrointestinal tract (GIT) in teleosts, but the respiratory conditions inside the GIT remain largely unknown, particularly the luminal PCO2 and PO2 levels. The GIT of seawater teleosts is of special interest due to its additional function of water absorption linked to HCO3- secretion, a process that may raise luminal PCO2 levels. Direct measurements of GIT PCO2 and PO2 using micro-optodes in the English sole (Parophrys vetulus; anaesthetized, artificially ventilated, 10-12 °C) revealed extreme luminal gas levels. Luminal PCO2 was 14-17 mmHg in the stomach and intestinal segments of fasted sole, considerably higher than arterial blood levels of 5 mmHg. Moreover, feeding, which raised intestinal HCO3- concentration, also raised luminal PCO2 to 34-50 mmHg. All these values were higher than comparable measurements in freshwater teleosts, and also greater than environmental CO2 levels of concern in aquaculture or global change scenarios. The PCO2 values in subintestinal vein blood draining the GIT of fed fish (28 mmHg) suggested some degree of equilibration with high luminal PCO2, whereas subintestinal vein PO2 levels were relatively low (9 mmHg). All luminal sections of the GIT were virtually anoxic (PO2 ≤ 0.3 mmHg), in both fasted and fed animals, a novel finding in teleosts.
Collapse
|
8
|
Barany A, Shaughnessy CA, Fuentes J, Mancera JM, McCormick SD. Osmoregulatory role of the intestine in the sea lamprey ( Petromyzon marinus). Am J Physiol Regul Integr Comp Physiol 2019; 318:R410-R417. [PMID: 31747320 DOI: 10.1152/ajpregu.00033.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Lampreys are the most basal vertebrates with an osmoregulatory strategy. Previous research has established that the salinity tolerance of sea lamprey increases dramatically during metamorphosis, but underlying changes in the gut have not been examined. In the present work, we examined changes in intestinal function during metamorphosis and seawater exposure of sea lamprey (Petromyzon marinus). Fully metamorphosed juvenile sea lamprey had 100% survival after direct exposure to 35 parts per thousand seawater (SW) and only slight elevations in plasma chloride (Cl-) levels. Drinking rates of sea lamprey juveniles in seawater were 26-fold higher than juveniles in freshwater (FW). Na+-K+-ATPase (NKA) activity in the anterior and posterior intestine increased 12- and 3-fold, respectively, during metamorphosis, whereas esophageal NKA activity was lower than in the intestine and did not change with development. Acclimation to SW significantly enhanced NKA activity in the posterior intestine but did not significantly change NKA activity in the anterior intestine, which remained higher than that in the posterior intestine. Intestinal Cl- and water uptake, which were observed in ex vivo preparations of anterior and posterior intestine under both symmetric and asymmetric conditions, were higher in juveniles than in larvae and were similar in magnitude of those of teleost fish. Inhibition of NKA by ouabain in ex vivo preparations inhibited intestinal water absorption by 64%. Our results indicate drinking and intestinal ion and water absorption are important to osmoregulation in SW and that preparatory increases in intestinal NKA activity are important to the development of salinity tolerance that occurs during sea lamprey metamorphosis.
Collapse
Affiliation(s)
- A Barany
- Department of Biology, Faculty of Marine and Environmental Sciences, Campus de Excelencia Internacional del Mar, University of Cádiz, Cádiz, Spain.,Centre of Marine Sciences, University of Algarve, Gambelas, Faro, Portugal
| | - C A Shaughnessy
- United States Geological Survey, Leetown Science Center, S.O. Conte Anadromous Fish Research Laboratory, Turners Falls, Massachusetts
| | - J Fuentes
- Centre of Marine Sciences, University of Algarve, Gambelas, Faro, Portugal
| | - J M Mancera
- Department of Biology, Faculty of Marine and Environmental Sciences, Campus de Excelencia Internacional del Mar, University of Cádiz, Cádiz, Spain
| | - S D McCormick
- United States Geological Survey, Leetown Science Center, S.O. Conte Anadromous Fish Research Laboratory, Turners Falls, Massachusetts.,Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts
| |
Collapse
|
9
|
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
|
10
|
Zhang D, Wang F, Dong S, Lu Y. De novo assembly and transcriptome analysis of osmoregulation in Litopenaeus vannamei under three cultivated conditions with different salinities. Gene 2015; 578:185-93. [PMID: 26691500 DOI: 10.1016/j.gene.2015.12.026] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 12/07/2015] [Accepted: 12/09/2015] [Indexed: 01/13/2023]
Abstract
Litopenaeus vannamei, one of the most important euryhaline crustaceans, is cultured in seawater, brackish water, and freshwater worldwide. We performed Illumina RNA sequencing of L. vannamei gills, generating 124,914,870; 119,250,450; and 105,487,350 raw reads from the shrimps cultured in seawater, brackish water, and freshwater, respectively. From these reads, 466,293 transcripts were de novo assembled and annotated. Comparative genomic analysis showed that 1752 genes were significantly differentially expressed in the freshwater group compared with the seawater group, including 1242 upregulated and 510 downregulated genes. In addition, 1246 genes were differentially expressed in the brackish group vs. the seawater water group, including 659 upregulated and 587 downregulated genes. These differentially expressed genes were mainly involved in energy metabolism, substance metabolism, ion transport and signal transduction, and genetic process. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis were used to analyze the functional significance of the differentially expressed genes, included those responding to salinity through diverse biological functions and processes and numerous potential genes associated with the osmotic response. L. vannamei responses to the three cultivated salinities were analyzed using next-generation sequencing. The transcriptional database established from the current research adds to the information available on L. vannamei and the findings expand our knowledge of the molecular basis of osmoregulation mechanisms in this species.
Collapse
Affiliation(s)
- Dan Zhang
- The Key Laboratory of Mariculture, Ministry of Education, Fisheries College, Ocean University of China, Qingdao, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Fang Wang
- The Key Laboratory of Mariculture, Ministry of Education, Fisheries College, Ocean University of China, Qingdao, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
| | - Shuanglin Dong
- The Key Laboratory of Mariculture, Ministry of Education, Fisheries College, Ocean University of China, Qingdao, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Yunliang Lu
- The Key Laboratory of Mariculture, Ministry of Education, Fisheries College, Ocean University of China, Qingdao, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| |
Collapse
|
11
|
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]
|
12
|
Gregório SF, Carvalho ESM, Campinho MA, Power DM, Canário AVM, Fuentes J. Endocrine regulation of carbonate precipitate formation in marine fish intestine by stanniocalcin and PTHrP. ACTA ACUST UNITED AC 2014; 217:1555-62. [PMID: 24501133 DOI: 10.1242/jeb.098517] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In marine fish, high epithelial bicarbonate secretion by the intestine generates luminal carbonate precipitates of divalent cations that play a key role in water and ion homeostasis. In vitro studies highlight the involvement of the calciotropic hormones PTHrP (parathyroid hormone-related protein) and stanniocalcin (STC) in the regulation of epithelial bicarbonate transport. The present study tested the hypothesis that calciotropic hormones have a regulatory role in carbonate precipitate formation in vivo. Sea bream (Sparus aurata) juveniles received single intraperitoneal injections of piscine PTHrP(1-34), the PTH/PTHrP receptor antagonist PTHrP(7-34) or purified sea bream STC, or were passively immunized with polyclonal rabbit antisera raised against sea bream STC (STC-Ab). Endocrine effects on the expression of the basolateral sodium bicarbonate co-transporter (Slc4a4.A), the apical anion exchangers Slc26a6.A and Slc26a3.B, and the V-type proton pump β-subunit (Atp6v1b) in the anterior intestine were evaluated. In keeping with their calciotropic nature, the hypocalcaemic factors PTHrP(7-34) and STC up-regulated gene expression of all transporters. In contrast, the hypercalcaemic factor PTHrP(1-34) and STC antibodies down-regulated transporters involved in the bicarbonate secretion cascade. Changes in intestine luminal precipitate contents provoked by calcaemic endocrine factors validated these results: 24 h post-injection either PTHrP(1-34) or immunization with STC-Ab reduced the carbonate precipitate content in the sea bream intestine. In contrast, the PTH/PTHrP receptor antagonist PTHrP(7-34) increased not only the precipitated fraction but also the concentration of HCO3(-) equivalents in the intestinal fluid. These results confirm the hypothesis that calciotropic hormones have a regulatory role in carbonate precipitate formation in vivo in the intestine of marine fish. Furthermore, they illustrate for the first time in fish the counteracting effect of PTHrP and STC, and reveal an unexpected contribution of calcaemic factors to acid-base balance.
Collapse
Affiliation(s)
- Sílvia F Gregório
- Centre of Marine Sciences (CCMar), Campus de Gambelas, Universidade do Algarve, 8005-139 Faro, Portugal
| | | | | | | | | | | |
Collapse
|
13
|
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
|
14
|
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
|
15
|
|
16
|
Osmoregulation and epithelial water transport: lessons from the intestine of marine teleost fish. J Comp Physiol B 2011; 182:1-39. [DOI: 10.1007/s00360-011-0601-3] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2011] [Revised: 06/08/2011] [Accepted: 06/15/2011] [Indexed: 12/15/2022]
|
17
|
Grosell M. Intestinal anion exchange in marine teleosts is involved in osmoregulation and contributes to the oceanic inorganic carbon cycle. Acta Physiol (Oxf) 2011; 202:421-34. [PMID: 21362153 DOI: 10.1111/j.1748-1716.2010.02241.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Marine teleost fish osmoregulation involves seawater ingestion and intestinal fluid absorption. Solute coupled fluid absorption by the marine teleost fish intestine has long been believed to be the product of Na(+) and Cl(-) absorption via the Na(+) :K(+) :2Cl(-) co-transporter (NKCC2). However, the past decade has revealed that intestinal anion exchange contributes significantly to Cl(-) absorption, in exchange for HCO(3) (-) secretion, and that this process is important for intestinal water absorption. In addition to contributing to solute coupled water absorption intestinal anion exchange results in luminal precipitation of CaCO(3) which acts to reduce luminal osmotic pressure and thus assist water absorption. Most recently, activity of apical H(+) -pumps, especially in distal segments of the intestine have been suggested to not only promote anion exchange, but also to reduce luminal osmotic pressure by preventing excess HCO(3)(-) concentrations from accumulating in intestinal fluids, thereby aiding water absorption. The present review summarizes and synthesizes the most recent advances in our view of marine teleosts osmoregulation, including our emerging understanding of epithelial transport of acid-base equivalents in the intestine, the consequences for whole organism acid-base balance and finally the impact of piscine CaCO(3) formation on the global oceanic carbon cycle.
Collapse
Affiliation(s)
- M Grosell
- RSMAS, University of Miami, Miami, FL 33149-1098, USA.
| |
Collapse
|
18
|
Peh WYX, Chew SF, Ching BY, Loong AM, Ip YK. Roles of intestinal glutamate dehydrogenase and glutamine synthetase in environmental ammonia detoxification in the euryhaline four-eyed sleeper, Bostrychus sinensis. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 98:91-98. [PMID: 20189662 DOI: 10.1016/j.aquatox.2010.01.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 12/16/2009] [Accepted: 01/25/2010] [Indexed: 05/28/2023]
Abstract
This study aimed to examine the hypothesis that intestinal glutamate dehydrogenase (GDH) and glutamine synthetase (GS) could be involved in ammonia detoxification in the euryhaline Bostrychus sinensis exposed to ammonia in a hyperosmotic environment, whereby drinking was essential for osmoregulation. Our results indicate that there was a significant increase in ammonia content in the intestine of B. sinensis exposed to 15 mmol l(-1) NH(4)Cl in seawater (pH 7.0) for 6 days. There were also significant increases in the amination and deamination activities and protein abundance of intestinal GDH. The GDH amination/deamination ratio remained unchanged, indicating that there could be increases in the turnover of glutamate. However, the difference between the amination and deamination activities increased 2-fold, implying that there could be an increase in glutamate formation in the intestine. Since the intestinal glutamate content remained unchanged, excess glutamate formed might have been channeled into other amino acids and/or transported to other organs. Indeed, the intestinal glutamine content increased significantly by 2-fold, with a significant increase in the activity and protein abundance of intestinal GS. Since the magnitude of glutamine accumulation in the intestine was lower than those in liver and muscle, which lacked changes in GDH activities, intestinal glutamate could have been shuttled to liver and muscle to facilitate increased synthesis of glutamine therein. By contrast, when fish were exposed to a much higher concentration (30 mmol l(-1)) of NH(4)Cl in 5 per thousand water (pH. 7.0), the magnitude of increase in ammonia content in the intestine was less prominent, and there were no changes in activities and kinetic properties of intestinal GDH. Therefore, it can be concluded that the intestine of B. sinensis was involved in the defense against ammonia toxicity during exposure to ammonia in a hyperosmotic medium.
Collapse
Affiliation(s)
- W Y X Peh
- Department of Biological Science, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | | | | | | | | |
Collapse
|
19
|
|
20
|
Eddy FB. Drinking in juvenile Atlantic salmon (Salmo salar L.) in response to feeding and activation of the endogenous renin–angiotensin system. Comp Biochem Physiol A Mol Integr Physiol 2007; 148:23-8. [PMID: 16978894 DOI: 10.1016/j.cbpa.2006.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Revised: 07/27/2006] [Accepted: 08/01/2006] [Indexed: 10/24/2022]
Abstract
Drinking rate and rectal fluid production of juvenile Atlantic salmon (1-2 g) in freshwater were investigated in unfed fish and recently fed fish. Drinking was also investigated following activation of the renin-angiotensin system (RAS) by two hypotensive agents, a nitric oxide (NO) donor sodium nitroprusside (SNP) and bacterial lipopolysaccharide (LPS). In unfed fish the basal drinking rate was 0.13 microL g(-1) h(-1) and rectal fluid production was 0.076 microL g(-1) h(-1). In recently fed fish both drinking rate and rectal fluid production increased significantly by about fivefold compared to unfed fish, and similar values were obtained for fish exposed to PS for 24 h. Exposure to SNP resulted in about a tenfold elevation of drinking rate and rectal fluid production, compared to unfed fish. Absorption of water by the gut was in the range 35-60% for all treatments. Drinking may have a role in processing food in the gut and the fluid in the gut may subjected to absorptive and secretory processes. The most likely route for removal of water absorbed by the gut is excretion via the kidney and this would result in an increased osmoregulatory burden on the fish. In polluted waters drinking could be increased through stimulation of the endogenous RAS by vasodilators, e.g., LPS and the gut could be a significant target for toxin exposure.
Collapse
Affiliation(s)
- F Brian Eddy
- Division of Environmental and Applied Biology, School of Life Sciences, University of Dundee, Dundee DD1 4HN, UK.
| |
Collapse
|
21
|
Grosell M, Gilmour KM, Perry SF. Intestinal carbonic anhydrase, bicarbonate, and proton carriers play a role in the acclimation of rainbow trout to seawater. Am J Physiol Regul Integr Comp Physiol 2007; 293:R2099-111. [PMID: 17761514 DOI: 10.1152/ajpregu.00156.2007] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abrupt transfer of rainbow trout from freshwater to 65% seawater caused transient disturbances in extracellular fluid ionic composition, but homeostasis was reestablished 48 h posttransfer. Intestinal fluid chemistry revealed early onset of drinking and slightly delayed intestinal water absorption that coincided with initiation of NaCl absorption and HCO(3)(-) secretion. Suggestive of involvement in osmoregulation, relative mRNA levels for vacuolar H(+)-ATPase (V-ATPase), Na(+)-K(+)-ATPase, Na(+)/H(+) exchanger 3 (NHE3), Na(+)-HCO(3)(-) cotransporter 1, and two carbonic anhydrase (CA) isoforms [a general cytosolic isoform trout cytoplasmic CA (tCAc) and an extracellular isoform trout membrane-bound CA type IV (tCAIV)], were increased transiently in the intestine following exposure to 65% seawater. Both tCAc and tCAIV proteins were localized to apical regions of the intestinal epithelium and exhibited elevated enzymatic activity after acclimation to 65% seawater. The V-ATPase was localized to both basolateral and apical regions and exhibited a 10-fold increase in enzymatic activity in fish acclimated to 65% seawater, suggesting a role in marine osmoregulation. The intestinal epithelium of rainbow trout acclimated to 65% seawater appears to be capable of both basolateral and apical H(+) extrusion, likely depending on osmoregulatory status and intestinal fluid chemistry.
Collapse
Affiliation(s)
- Martin Grosell
- Rosensteil School of Marine Atmospheric Sciences, University of Miami, FL 33149-1098, USA.
| | | | | |
Collapse
|
22
|
Tipsmark CK, Luckenbach JA, Madsen SS, Borski RJ. IGF-I and branchial IGF receptor expression and localization during salinity acclimation in striped bass. Am J Physiol Regul Integr Comp Physiol 2007; 292:R535-43. [PMID: 16959864 DOI: 10.1152/ajpregu.00915.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The initial response of the IGF-I system and the expression and cellular localization of IGF type-I receptor (IGF-IR) were studied in the gill of a euryhaline teleost during salinity acclimation. Exposure of striped bass ( Morone saxatilis) to hyperosmotic and hypoosmotic challenges induced small, transitory (<24 h) deflections in hydromineral balance. Transfer from freshwater (FW) to seawater (SW) induced an initial decrease in plasma IGF-I levels after 24 h in both fed and fasted fish. There was an overall decrease in liver IGF-I mRNA levels after SW transfer, suggesting that decreased plasma levels may be due to a decline in hepatic IGF-I synthesis. No changes were observed in gill IGF-I mRNA, but SW transfer induced an increase in gill IGF-IR mRNA after 24 h. Transfer from SW to FW induced an increase in plasma IGF-I levels in fasted fish. In fed fish, no significant changes were observed in either plasma IGF-I, liver, or gill IGF-I mRNA, or gill IGF-IR mRNA levels. In a separate experiment, FW-acclimated fish were injected with saline or IGF-I prior to a 24-h SW challenge. Rapid regain of osmotic balance following SW transfer was hindered by IGF-I. Immunohistochemistry revealed for the first time in teleosts that IGF-IR and Na+-K+-ATPase are localized in putative chloride cells at the base of the lamellae, identifying these cells in the gill as a target for IGF-I and IGF-II. Overall the data suggest a hyperosmoregulatory role of IGF-I in this species.
Collapse
|
23
|
Eddy FB. Role of nitric oxide in larval and juvenile fish. Comp Biochem Physiol A Mol Integr Physiol 2005; 142:221-30. [PMID: 15979364 DOI: 10.1016/j.cbpb.2005.05.038] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2005] [Revised: 05/11/2005] [Accepted: 05/12/2005] [Indexed: 10/25/2022]
Abstract
Fish are known to express the three isoforms of nitric oxide synthase (NOS), the constitutive forms endothelial or eNOS, neuronal or nNOS and the inducible form iNOS. Most studies in fish have focussed on possible roles for NO in cardiovascular physiology although there has been recent attention on the role of nNOS in embryonic development. However compared to mammalian studies there have been relatively few studies on effects of nitric oxide (NO) on fish. Studies on heart and blood vessel preparations from various fish species appear to show results specific to the species or to the particular preparation. Possible roles of NO in the in vivo biology of adult fish or larval fish have received little attention. This article reviews effects of nitric oxide on cardiovascular physiology in fish with special emphasis on larval fish. It introduces some experimental work on possible signaling pathways in larval fish and introduces the possibility that NO could be an important environmental influence for some aquatic organisms. In higher vertebrates LPS (lipopolysaccharide) is known to activate the cytokine signaling system and stimulate increased expression of iNOS and increased production of NO, but this remains less investigated in fish. The effects of LPS on cardiovascular and osmoregulatory physiology of larval and juvenile salmonids are discussed and a possible role of NO in stress-induced drinking is suggested.
Collapse
Affiliation(s)
- F B Eddy
- Biological Sciences Institute, Faculty of Life Sciences, University of Dundee DD1 4HN, UK.
| |
Collapse
|
24
|
Best JH, Eddy FB, Codd GA. Effects of Microcystis cells, cell extracts and lipopolysaccharide on drinking and liver function in rainbow trout Oncorhynchus mykiss Walbaum. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2003; 64:419-426. [PMID: 12878412 DOI: 10.1016/s0166-445x(03)00105-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Liver mass (hepatosomatic index, HSI) increased by approximately 18% and water content in the gut by approximately 13 ml kg(-1) in freshwater rainbow trout exposed for 24 h to intact cells of a microcystin-producing cyanobacterium (Microcystis PCC 7813) together with administration of heterotrophic bacterial LPS. Exposure to broken (ultrasonicated) cyanobacterial cells together with administration of bacterial LPS increased HSI by approximately 50% and water content in the gut by almost 30 ml kg(-1). Exposure to broken or unbroken Microcystis cells without administration of bacterial LPS resulted in increased water content of the gut (by approximately 13 ml kg(-1)) with insignificant changes in HIS. Drinking rate increased with increasing dosage of bacterial LPS alone. The increased volume of water in the gut potentially increases the opportunity for uptake of waterborne toxins, including microcystins, and increased liver mass is a symptom consistent with the toxic effects of microcystins. It is concluded that exposure of fish to the cell contents of cyanobacteria (e.g. Microcystis PCC 7813) promotes osmoregulatory imbalance resulting from stimulation of the drinking response, increased volume of fluid in the gut and inability to remove excess water.
Collapse
Affiliation(s)
- J H Best
- Division of Environmental and Applied Biology, School of Life Sciences, University of Dundee, DD1 4HN Dundee, UK
| | | | | |
Collapse
|
25
|
Rankin JC, Cobb CS, Frankling SC, Brown JA. Circulating angiotensins in the river lamprey, Lampetra fluviatilis, acclimated to freshwater and seawater: possible involvement in the regulation of drinking. Comp Biochem Physiol B Biochem Mol Biol 2001; 129:311-8. [PMID: 11399464 DOI: 10.1016/s1096-4959(01)00336-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Plasma angiotensin levels were measured for the first time in a cyclostome, the river lamprey. With the demonstration that angiotensins are present in the circulation, the possibility of a physiological role in the regulation of drinking was re-examined. Angiotensin II and III concentrations and plasma osmolalities were significantly higher in lampreys acclimated to 28 ppt seawater than in those acclimated to freshwater. No changes were found in angiotensin II and III levels 4 h after transfer from freshwater to 50% seawater, although plasma osmolality had started to rise by this time. There was a suggestion that plasma angiotensin II levels might be related to osmolality in the transfer experiment. Injection of Asp(1)Val(5)- or Asn(1)Val(5)-angiotensin II (40-169 microg/kg body wt.) did not stimulate drinking in freshwater-acclimated lampreys, even when they were still capable of drinking. The angiotensin-converting enzyme inhibitor captopril and the smooth muscle relaxant papaverine both reduced drinking rate in 50% seawater-acclimated lampreys. The data do not provide direct evidence for the involvement of the renin-angiotensin system in the control of drinking behaviour in the lamprey. Indirect evidence from the captopril effect is suggestive, but could have other explanations.
Collapse
Affiliation(s)
- J C Rankin
- Aquatic Biology Research Centre, Odense University, Hindsholmvej 11, 5300, Kerteminde, Denmark.
| | | | | | | |
Collapse
|
26
|
Takei Y, Tsuchida T. Role of the renin-angiotensin system in drinking of seawater-adapted eels Anguilla japonica: a reevaluation. Am J Physiol Regul Integr Comp Physiol 2000; 279:R1105-11. [PMID: 10956272 DOI: 10.1152/ajpregu.2000.279.3.r1105] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The role of ANG II, a potent dipsogenic hormone, in copious drinking of seawater eels was examined. SQ-14225 (SQ), an angiotensin-converting enzyme inhibitor, infused intra-arterially at 0.01-1 microgram. kg(-1). min(-1), depressed drinking and arterial blood pressure in a dose-dependent manner. The inhibition was accompanied by a small decrease in plasma ANG II concentration, which became significant at 1 microgram. kg(-1). min(-1). After the infusate was changed back to the vehicle, the depression of drinking and arterial pressure continued for >2 h, although plasma ANG II concentration rebounded above the level before SQ infusion. By contrast, infusion of anti-ANG II serum (0.01-1 microgram. kg(-1). min(-1)) did not suppress drinking and arterial pressure, although plasma ANG II concentration decreased to undetectable levels. Plasma atrial natriuretic peptide and plasma osmolality, which influence drinking rate in eels, did not change during SQ or antiserum infusions. These results suggest that the renin-angiotensin system plays only a minor role in the vigorous drinking observed in seawater eels. The results also suggest that the antidipsogenic and vasodepressor effects of SQ in seawater eels are not due solely to the inhibition of ANG II formation in plasma.
Collapse
Affiliation(s)
- Y Takei
- Ocean Research Institute, The University of Tokyo, Tokyo 164-8639, Japan.
| | | |
Collapse
|
27
|
Tsuchida T, Takei Y. A Potent Dipsogenic Action of Homologous Angiotensin II Infused at Physiological Doses in Eels. Zoolog Sci 1999. [DOI: 10.2108/zsj.16.479] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|