Social stress reduces forebrain cell proliferation in rainbow trout (Oncorhynchus mykiss)

2012 ◽  
Vol 227 (2) ◽  
pp. 311-318 ◽  
Author(s):  
Christina Sørensen ◽  
Göran E. Nilsson ◽  
Cliff H. Summers ◽  
Øyvind Øverli
Keyword(s):  
Cell Proliferation ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Social Stress ◽  
Rainbow Trout Oncorhynchus Mykiss

Branchial chloride cell proliferation in the rainbow trout, Oncorhynchus mykiss: implications for gas transfer

1994 ◽  
Vol 72 (8) ◽  
pp. 1395-1402 ◽  
Author(s):  
Shawn D. Bindon ◽  
James C. Fenwick ◽  
Steve F. Perry
Keyword(s):  
Electron Microscopy ◽  
Cell Proliferation ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Surface Area ◽  
Chloride Cell ◽  
Gas Transfer ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Treated Fish ◽  
Fractional Surface

The effects of branchial chloride cell proliferation on ion transport capability and gill morphometry were evaluated in the rainbow trout, Oncorhynchus mykiss, to test the hypothesis that chloride cell (CC) proliferation benefits ionic regulation at the expense of efficient gas transfer. The extent of hormone-induced CC proliferation (using ovine growth hormone (oGH), cortisol, or a combination of both) on the gill filament epithelium was assessed by determining the fractional surface area of exposed cells using scanning electron microscopy. Cortisol and oGH were equally effective in increasing CC fractional surface area (~2×), owing to the enlargement of individual CCs. The combined cortisol/oGH treatment resulted in an even greater increase in CC fractional area (~6×), as both the size and number of CCs increased. Sham injections were without effect on CC surface area or number. Significant increases in Na+ (Jin Na+) and Cl− uptake (Jin Cl−) were observed after all hormone treatments and were correlated positively with the increases in the CC fractional surface area. These findings support the view that CC proliferation enhances branchial ion transport capability. Lamellar epithelial thickness (measured by transmission electron microscopy) was increased in hormone-treated fish, while lamellar surface area (measured using light microscopy) was unaffected. The area of the interlamellar water channels (calculated from light micrographs) was significantly reduced in hormone-treated fish. These results suggest that, in trout, a compromise is made between the efficiency of ion regulation and gas transfer in which the enlargement/proliferation of CCs may impede gas transfer.

scholarly journals Regulation of proliferation and differentiation of adipocyte precursor cells in rainbow trout (Oncorhynchus mykiss)

2008 ◽  
Vol 198 (3) ◽  
pp. 459-469 ◽  
Author(s):  
L Bouraoui ◽  
J Gutiérrez ◽  
I Navarro
Keyword(s):  
Cell Proliferation ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Adipocyte Differentiation ◽  
Nuclear Antigen ◽  
Peroxisome Proliferator ◽  
Endocrine Regulation ◽  
Endocrine Control ◽  
Insulin Growth Factor ◽  
Rainbow Trout Oncorhynchus Mykiss

Here, we describe optimal conditions for the culture of rainbow trout (Oncorhynchus mykiss) pre-adipocytes obtained from adipose tissue and their differentiation into mature adipocytes, in order to study the endocrine control of adipogenesis. Pre-adipocytes were isolated by collagenase digestion and cultured on laminin or 1% gelatin substrate. The expression of proliferating cell nuclear antigen was used as a marker of cell proliferation on various days of culture. Insulin growth factor-I stimulated cell proliferation especially on days 5 and 7 of culture. Tumor necrosis factor α (TNFα) slightly enhanced cell proliferation only at a low dose. We verified the differentiation of cells grown in specific medium into mature adipocytes by oil red O (ORO) staining. Quantification of ORO showed an increase in triglycerides throughout culture. Immunofluorescence staining of cells at day 11 revealed the expression of CCAAT/enhancer-binding protein and peroxisome proliferator–activator receptor γ, suggesting that these transcriptional factors are involved in adipocyte differentiation in trout. We also examined the effect of TNFα on the differentiation of these adipocytes in primary culture. TNFα inhibited the differentiation of these cells, as indicated by a decrease in glycerol-3-phosphate dehydrogenase activity, an established marker of adipocyte differentiation. In conclusion, the culture system described here for trout pre-adipocytes is a powerful tool to study the endocrine regulation of adipogenesis in this species.

scholarly journals Elevated cortisol lowers thermal tolerance but results in limited cardiac remodelling in rainbow trout (Oncorhynchus mykiss) experiencing chronic social stress

2021 ◽  
Author(s):  
Brittany Bard ◽  
Annette Dodge ◽  
William Joyce ◽  
Michael Lawrence ◽  
Steven J Cooke ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Social Stress ◽  
Thermal Tolerance ◽  
Cardiac Remodelling ◽  
Type I ◽  
Chronic Social Stress ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Dominant Fish ◽  
Cortisol Levels

Juvenile rainbow trout (Oncorhynchus mykiss) held in pairs form dominance hierarchies in which subordinate individuals experience chronic social stress accompanied by lowered thermal tolerance (assessed as the critical thermal maximum, CTmax). Here we tested the hypothesis that chronic elevation of circulating cortisol levels reduces thermal tolerance in subordinate trout. In support of this hypothesis, subordinate trout that recovered from social stress for 48 h, a period sufficient to return cortisol to normal baseline levels, no longer showed reduced CTmax. Further, thermal tolerance was not restored in subordinates treated with cortisol during recovery from social stress. To explore possible mechanisms underlying the effect of chronic stress on CTmax, we also tested the hypothesis that chronic cortisol elevation induces cardiac remodelling in subordinate trout, as previously reported for cortisol-treated rainbow trout. Ventricle mass and cardiac hypertrophy markers were unaffected by social stress. Picrosirius red staining revealed a trend for lower collagen levels in the ventricles of subordinate relative to dominant trout. However, collagen type I transcript and protein levels, and markers of collagen turnover were unaffected. Indicators of cardiac function, including ventricle passive stiffness and intrinsic heart rate (fH), similarly were unaffected. In vivo fH was also similar between subordinate and dominant fish. Nevertheless, in keeping with their lower CTmax, subordinate fish exhibited cardiac arrhythmia at significantly lower temperatures than dominant fish during CTmax trials. Thus, high baseline cortisol levels in subordinate trout result in lowered thermal tolerance, but 5 d of social stress did not greatly affect cardiac structure and function.

Cortisol reduces cell proliferation in the telencephalon of rainbow trout (Oncorhynchus mykiss)

2011 ◽  
Vol 102 (5) ◽  
pp. 518-523 ◽  
Author(s):  
Christina Sørensen ◽  
Linda C. Bohlin ◽  
Øyvind Øverli ◽  
Göran E. Nilsson
Keyword(s):  
Cell Proliferation ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Rainbow Trout Oncorhynchus Mykiss
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