The resting membrane potential of white muscle from brown trout (Salmo trutta) exposed to copper in soft, acidic water

2000 ◽  
Vol 203 (14) ◽  
pp. 2229-2236 ◽  
Author(s):  
M.W. Beaumont ◽  
E.W. Taylor ◽  
P.J. Butler
Keyword(s):  
Membrane Potential ◽  
Brown Trout ◽  
Salmo Trutta ◽  
White Muscle ◽  
Low Ph ◽  
Ammonium Ion ◽  
Muscle Membrane ◽  
Resting Membrane Potential ◽  
Muscle Fibres ◽  
Brown Trout Salmo Trutta

Previously, the distribution of ammonia between the intracellular and extracellular compartments has been used to predict a significant depolarisation of the resting membrane potential (E(M)) of white muscle from brown trout (Salmo trutta) exposed to a sub-lethal combination of copper and low pH. However, this prediction is based upon two assumptions (i) a relatively high membrane permeability for the ammonium ion with respect to that for ammonia gas and (ii) that this is unaltered by exposure to copper and low pH. Since there is conflicting evidence in the literature of the validity of these assumptions, in the present study E(M) was directly measured in white muscle fibres of trout exposed to copper and low pH (E(M)=−52.2+/−4.9 mV) and compared with that of unexposed, control animals (E(M)=−86.5+/−2.9 mV) (means +/− s.e.m., N=6). In confirming the predicted depolarisation, these data support the hypothesis of electrophysiological impairment as a factor in the reduction in the swimming performance of trout exposed to these pollutants. In addition, the results of this study support the role of a significant permeability of the muscle membrane to NH(4)(+) in determining the distribution of ammonia in fish.

Influence of low pH on brown trout, Salmo trutta

1991 ◽  
Vol 24 (4) ◽  
pp. 2470-2473
Author(s):  
Helmut Segner ◽  
Harald Gebhardt ◽  
Michael Linnenbach ◽  
Roland Marthaler ◽  
Andreas Ness
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Low Ph ◽  
Brown Trout Salmo Trutta

Environmental acidity and white muscle recruitment during swimming in the brown trout (Salmo trutta)

1996 ◽  
Vol 199 (9) ◽  
pp. 1947-1959
Author(s):  
N Day ◽  
P Butler
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
White Muscle ◽  
Muscle Recruitment ◽  
Neutral Ph ◽  
Exercise Period ◽  
Brown Trout Salmo Trutta ◽  
Burst Swimming ◽  
The Mean ◽  
Glycogen Stores

Electromyographic recordings show that, for adult brown trout swum up to their critical swimming speed (Ucrit) in a flume at neutral pH, white muscle recruitment occurred when speeds approached 1 body length s-1 (BL s-1) and continued to Ucrit (approximately 2 BL s-1) at both winter (5 °C) and summer (15 °C) acclimation temperatures. However, in the majority of fish swum up to Ucrit at sublethal acidic pH, continuous white muscle recruitment did not occur, although all swam above 1 BL s-1. Any observed electrical activity of the white muscle in these individuals was, at best, intermittent. Consequently, the mean Ucrit of these fish was approximately half that of fish swum at neutral pH. In all fish at sublethal pH, red muscle activity was observed for the whole duration of the exercise period, showing that swimming speeds greater than 1 BL s-1 were achieved largely aerobically. Fish that were chased around a tank at sublethal pH appeared lethargic in their escape response, exhibiting little or no burst swimming. Other observed effects of exposure to sublethal pH, which may have affected swimming capacity, included increases in the resting levels of blood and muscle ammonia, reduced muscle glycogen stores and reduced muscle ion concentrations.

Sign in / Sign up

Export Citation Format

Share Document