Document Detail

Plasma ammonia concentration in brown trout in soft acidic water and its relationship to decreased swimming performance
MedLine Citation:
PMID:  9320125     Owner:  NLM     Status:  Publisher    
Adult brown trout (300­600 g) were acclimated for 2 weeks to an artificial soft water (Ca2+, 50 µmol l-1) and maintained at either 5 °C (October to March) or 15 °C (May to August). Following insertion of a cannula into the dorsal aorta under MS-222 anaesthesia and a recovery period of 2 days, the fish were exposed to a 4 day episode of sub-lethal copper levels at pH 5 or kept at control conditions of pH 7 without copper. The copper concentrations had been predetermined by toxicity testing and were approximately 0.47 µmol l-1 at 5 °C and 0.08 µmol l-1 at 15 °C. At 5 °C, a group of fish was also exposed to approximately 0.08 µmol l-1 copper at pH 5. Plasma total ammonia (Tamm) concentration was significantly elevated by exposure to copper and pH 5. In resting trout exposed to the appropriate sub-lethal copper concentration at pH 5, Tamm was six and 7.5 times greater at 5 and 15 °C, respectively, than those of control trout at the respective temperatures. Although unconfirmed, an elevation of ammonia production alone seems unlikely to account for such substantial increases. From previous studies, there is little evidence of impairment of respiratory gas exchange in trout exposed to these copper concentrations and yet, in the acidic test waters, the gradient of NH3 partial pressure between fish and water was 5.5­6 times greater than that under control conditions. Swimming performance determined by the critical swimming speed (Ucrit) was reduced by copper and acid exposure, and a significant relationship existed between Ucrit and the plasma ammonia concentration of exercised trout. Ammonium ions influence several key enzymes involved in energy metabolism, and elevated ammonia levels might, therefore, reduce the capacity of muscle to exercise. Alternatively, ammonia may have affected the nervous coordination of exercise either centrally or by disrupting peripheral motor innervation.
Beaumont; Butler; Taylor
Related Documents :
21267745 - Impact of heat and pollution on oxidative stress and cc16 secretion after 8 km run.
15892915 - Seasonal rhythms and exercise.
8321575 - Leisure-time physical activity as a determinant of self-perceived fitness.
24977955 - Long-term low-to-intensive cycling training: impact on semen parameters and seminal cyt...
18075235 - Exercise improves visual deficits tested by visual evoked potentials in streptozotocin-...
20135145 - Effects of wind and rain on thermal responses of humans in a mildly cold environment.
Publication Detail:
Journal Detail:
Title:  The Journal of experimental biology     Volume:  198     ISSN:  1477-9145     ISO Abbreviation:  J. Exp. Biol.     Publication Date:  1995  
Date Detail:
Created Date:  1997-10-07     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0243705     Medline TA:  J Exp Biol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  2213-20     Citation Subset:  -    
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  The locust DCMD, a movement-detecting neurone tightly tuned to collision trajectories
Next Document:  Influence of muscle length on work from trabecular muscle of frog atrium and ventricle