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Nephron 2016Vertebrates control the osmolality of their extra- and intra-cellular compartments despite large variations in salt and water intake. Aldosterone-dependent sodium... (Review)
Review
Vertebrates control the osmolality of their extra- and intra-cellular compartments despite large variations in salt and water intake. Aldosterone-dependent sodium reabsorption and vasopressin-dependent water transport in the distal nephron and collecting duct play a critical role in the final control of sodium and water balance. Long-term fasting (no eating, no drinking) represents an osmotic challenge for survival. Evolution has found very different solutions to meet this challenge. To illustrate this point, I will discuss osmoregulation of a mammal (elephant seal pup) and of a fish (lungfish) that are able to survive long-term fasting for months or even years. Homer W. Smith taught us how informative comparative anatomy and physiology of the kidney could help physiologists and nephrologists to better understand how the kidney works. In recent years, comparative genomics, transcriptomics and proteomics across the tree of life have led to the emergence of a new discipline, evolutionary medicine. In the near future, physiologists and nephrologists will benefit from this new field of investigation, thanks to its potential for the identification of novel drug targets and therapies.
Topics: Animals; Arginine Vasopressin; Biological Evolution; Fasting; Fishes; Osmoregulation; Renin-Angiotensin System; Seals, Earless
PubMed: 26901864
DOI: 10.1159/000444307 -
International Journal of Molecular... Aug 2022Smolting is an important development stage of salmonid, and an energy trade-off occurs between osmotic regulation and growth during smolting in rainbow trout...
Smolting is an important development stage of salmonid, and an energy trade-off occurs between osmotic regulation and growth during smolting in rainbow trout (Oncorhynchus mykiss). Growth hormone releasing hormone, somatostatin, growth hormone and insulin-like growth factor (GHRH-SST-GH-IGF) axis exhibit pleiotropic effects in regulating growth and osmotic adaptation. Due to salmonid specific genome duplication, increased paralogs are identified in the ghrh-sst-gh-igf axis, however, their physiology in modulating osmoregulation has yet to be investigated. In this study, seven sst genes (sst1a, sst1b, sst2, sst3a, sst3b, sst5, sst6) were identified in trout. We further investigated the ghrh-sst-gh-igf axis of diploid and triploid trout in response to seawater challenge. Kidney sst (sst1b, sst2, sst5) and sstr (sstr1b1, sstr5a, sstr5b) expressions were changed (more than 2-fold increase (except for sstr5a with 1.99-fold increase) or less than 0.5-fold decrease) due to osmoregulation, suggesting a pleiotropic physiology of SSTs in modulating growth and smoltification. Triploid trout showed significantly down-regulated brain sstr1b1 and igfbp2a1 (p < 0.05), while diploid trout showed up-regulated brain igfbp1a1 (~2.61-fold, p = 0.057) and igfbp2a subtypes (~1.38-fold, p < 0.05), suggesting triploid trout exhibited a better acclimation to the seawater environment. The triploid trout showed up-regulated kidney igfbp5a subtypes (~6.62 and 7.25-fold, p = 0.099 and 0.078) and significantly down-regulated igfbp5b2 (~0.37-fold, p < 0.05), showing a conserved physiology of teleost IGFBP5a in regulating osmoregulation. The IGFBP6 subtypes are involved in energy and nutritional regulation. Distinctive igfbp6 subtypes patterns (p < 0.05) potentially indicated trout triggered energy redistribution in brain and kidney during osmoregulatory regulation. In conclusion, we showed that the GHRH-SST-GH-IGF axis exhibited pleiotropic effects in regulating growth and osmoregulatory regulation during trout smolting, which might provide new insights into seawater aquaculture of salmonid species.
Topics: Animals; Growth Hormone; Growth Hormone-Releasing Hormone; Human Growth Hormone; Insulin-Like Growth Factor I; Oncorhynchus mykiss; Osmoregulation; Somatostatin; Triploidy
PubMed: 35955823
DOI: 10.3390/ijms23158691 -
Peritoneal Dialysis International :... 2013
Topics: Animals; Humans; Kidney; Osmoregulation; Peritoneal Dialysis; Vasopressins
PubMed: 24133076
DOI: 10.3747/pdi.2013.00169 -
American Journal of Physiology.... Jan 2016Evidence of increased reactive oxygen species (ROS) production is observed in the circulation during exercise in humans. This is exacerbated at elevated body... (Review)
Review
Evidence of increased reactive oxygen species (ROS) production is observed in the circulation during exercise in humans. This is exacerbated at elevated body temperatures and attenuated when normal exercise-induced body temperature elevations are suppressed. Why ROS production during exercise is temperature dependent is entirely unknown. This review covers the human exercise studies to date that provide evidence that oxidant and antioxidant changes observed in the blood during exercise are dependent on temperature and fluid balance. We then address possible mechanisms linking exercise with these variables that include shear stress, effects of hemoconcentration, and signaling pathways involving muscle osmoregulation. Since pathways of muscle osmoregulation are rarely discussed in this context, we provide a brief review of what is currently known and unknown about muscle osmoregulation and how it may be linked to oxidant production in exercise and hyperthermia. Both the circulation and the exercising muscle fibers become concentrated with osmolytes during exercise in the heat, resulting in a competition for available water across the muscle sarcolemma and other tissues. We conclude that though multiple mechanisms may be responsible for the changes in oxidant/antioxidant balance in the blood during exercise, a strong case can be made that a significant component of ROS produced during some forms of exercise reflect requirements of adapting to osmotic challenges, hyperthermia challenges, and loss of circulating fluid volume.
Topics: Adaptation, Physiological; Animals; Antioxidants; Blood Volume; Body Temperature Regulation; Dehydration; Exercise; Fever; Humans; Muscle Contraction; Muscle, Skeletal; Osmoregulation; Osmotic Pressure; Oxidative Stress; Reactive Oxygen Species; Water-Electrolyte Balance
PubMed: 26561649
DOI: 10.1152/ajpregu.00395.2015 -
Microbiome Sep 2021Coastal aquatic ecosystems include chemically distinct, but highly interconnected environments. Across a freshwater-to-marine transect, aquatic communities are exposed...
BACKGROUND
Coastal aquatic ecosystems include chemically distinct, but highly interconnected environments. Across a freshwater-to-marine transect, aquatic communities are exposed to large variations in salinity and nutrient availability as tidal cycles create periodic fluctuations in local conditions. These factors are predicted to strongly influence the resident microbial community structure and functioning, and alter the structure of aquatic food webs and biogeochemical cycles. Nevertheless, little is known about the spatial distribution of metabolic properties across salinity gradients, and no study has simultaneously surveyed the sediment and water environments. Here, we determined patterns and drivers of benthic and planktonic prokaryotic and microeukaryotic community assembly across a river and tidal lagoon system by collecting sediments and planktonic biomass at nine shallow subtidal sites in the summer. Genomic and transcriptomic analyses, alongside a suite of complementary geochemical data, were used to determine patterns in the distribution of taxa, mechanisms of salt tolerance, and nutrient cycling.
RESULTS
Taxonomic and metabolic profiles related to salt tolerance and nutrient cycling of the aquatic microbiome were found to decrease in similarity with increasing salinity, and distinct trends in diversity were observed between the water column and sediment. Non-saline and saline communities adopted divergent strategies for osmoregulation, with an increase in osmoregulation-related transcript expression as salinity increased in the water column due to lineage-specific adaptations to salt tolerance. Results indicated a transition from phosphate limitation in freshwater habitats to nutrient-rich conditions in the brackish zone, where distinct carbon, nitrogen and sulfur cycling processes dominated. Phosphorus acquisition-related activity was highest in the freshwater zone, along with dissimilatory nitrate reduction to ammonium in freshwater sediment. Activity associated with denitrification, sulfur metabolism and photosynthesis were instead highest in the brackish zone, where photosynthesis was dominated by distinct microeukaryotes in water (Cryptophyta) and sediment (diatoms). Despite microeukaryotes and archaea being rare relative to bacteria, results indicate that they contributed more to photosynthesis and ammonia oxidation, respectively.
CONCLUSIONS
Our study demonstrates clear freshwater-saline and sediment-water ecosystem boundaries in an interconnected coastal aquatic system and provides a framework for understanding the relative importance of salinity, planktonic-versus-benthic habitats and nutrient availability in shaping aquatic microbial metabolic processes, particularly in tidal lagoon systems. Video abstract.
Topics: Ecosystem; Microbiota; Nutrients; Osmoregulation; Plankton; Rivers
PubMed: 34544488
DOI: 10.1186/s40168-021-01145-3 -
Current Opinion in Neurobiology Aug 2019Fine balance between loss-of water and gain-of water is essential for maintaining body fluid homeostasis. The development of neural manipulation and mapping tools has... (Review)
Review
Fine balance between loss-of water and gain-of water is essential for maintaining body fluid homeostasis. The development of neural manipulation and mapping tools has opened up new avenues to dissect the neural circuits underlying body fluid regulation. Recent studies have identified several nodes in the brain that positively and negatively regulate thirst. The next step forward would be to elucidate how neural populations interact with each other to control drinking behavior.
Topics: Brain; Homeostasis; Thirst; Water-Electrolyte Balance
PubMed: 30836260
DOI: 10.1016/j.conb.2019.01.014 -
Anesthesiology May 2022
Topics: Diaphragm; Muscle Contraction; Respiration, Artificial; Water-Electrolyte Balance
PubMed: 35325037
DOI: 10.1097/ALN.0000000000004191 -
Journal of Postgraduate Medicine Jan 1980
Topics: Animals; Body Fluids; Dendrites; Diabetes Insipidus; Haplorhini; Hypothalamus; Inappropriate ADH Syndrome; Macaca mulatta; Osmolar Concentration; Sensory Receptor Cells; Vasopressins; Water-Electrolyte Balance
PubMed: 6768880
DOI: No ID Found -
The Journal of Clinical Investigation Mar 1988
Review
Topics: Animals; Diabetes Complications; Diabetes Mellitus; Diabetes Mellitus, Experimental; Humans; Kidney Medulla; Sorbitol; Water-Electrolyte Balance
PubMed: 3278002
DOI: 10.1172/JCI113366 -
Frontiers in Immunology 2021The transient receptor potential vanilloid 4 channel (TRPV4) is a non-selective cation channel that is widely expressed and activated by a range of stimuli. Amongst... (Review)
Review
The transient receptor potential vanilloid 4 channel (TRPV4) is a non-selective cation channel that is widely expressed and activated by a range of stimuli. Amongst these stimuli, changes in cell volume feature as a prominent regulator of TRPV4 activity with cell swelling leading to channel activation. In experimental settings based on abrupt introduction of large osmotic gradients, TRPV4 activation requires co-expression of an aquaporin (AQP) to facilitate such cell swelling. However, TRPV4 readily responds to cell volume increase irrespectively of the molecular mechanism underlying the cell swelling and can, as such, be considered a sensor of increased cell volume. In this review, we will discuss the proposed events underlying the molecular coupling from cell swelling to channel activation and present the evidence of direct indirect swelling-activation of TRPV4. With this summary of the current knowledge of TRPV4 and its ability to sense cell volume changes, we hope to stimulate further experimental efforts in this area of research to clarify TRPV4's role in physiology and pathophysiology.
Topics: Animals; Cell Size; Humans; Inflammation Mediators; Ion Channel Gating; Mechanotransduction, Cellular; Osmoregulation; TRPV Cation Channels
PubMed: 34616399
DOI: 10.3389/fimmu.2021.730982