The effects of hypoxia, in vivo, on red blood cell ?-adrenoceptors in the rainbow trout, Oncorhynchus mykiss

Unidirectional (36)Cl(−) efflux via the red blood cell anion exchanger was measured under Cl(−) self-exchange conditions (i.e. no net flow of anions) in rainbow trout Oncorhynchus mykiss and red-eared freshwater turtle Trachemys scripta to examine the effects of acute temperature changes and acclimation temperature on this process. We also evaluated the possible adaptation of anion exchange to different temperature regimes by including our previously published data on other animals. An acute temperature increase caused a significant increase in the rate constant (k) for unidirectional Cl(−) efflux in rainbow trout and freshwater turtle. After 3 weeks of temperature acclimation, 5 degrees C-acclimated rainbow trout showed only marginally higher Cl(−) transport rates than 15 degrees C-acclimated trout when compared at the same temperature. Apparent activation energies for red blood cell Cl(−) exchange in trout and turtle were lower than values reported in endothermic animals. The Q(10) for red blood cell anion exchange was 2.0 in trout and 2.3 in turtle, values close to those for CO(2) excretion, suggesting that, in ectothermic animals, the temperature sensitivity of band-3-mediated anion exchange matches the temperature sensitivity of CO(2) transport (where red blood cell Cl(−)/HCO(3)(−) exchange is a rate-limiting step). In endotherms, such as man and chicken, Q(10) values for red blood cell anion exchange are considerably higher but are no obstacle to CO(2) transport, because body temperature is normally kept constant at values at which anion exchange rates are high. When compared at constant temperature, red blood cell Cl(−) permeability shows large differences among species (trout, carp, eel, cod, turtle, alligator, chicken and man). Cl(−) permeabilities are, however, remarkable similar when compared at preferred body temperatures, suggesting an appropriate evolutionary adaptation of red blood cell anion exchange function to the different thermal niches occupied by animals.

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Myotomal slow muscle function of rainbow trout Oncorhynchus mykiss during steady swimming.

Journal of Experimental Biology ◽

10.1242/jeb.201.10.1659 ◽

1998 ◽

Vol 201 (10) ◽

pp. 1659-1671 ◽

Cited By ~ 22

Author(s):

L Hammond ◽

J D Altringham ◽

C S Wardle

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Body Length ◽

Muscle Activation ◽

Activity Patterns ◽

The Body ◽

Entire Body ◽

Negative Power ◽

Rainbow Trout Oncorhynchus Mykiss

Strain and activity patterns were determined during slow steady swimming (tailbeat frequency 1.5-2.5 Hz) at three locations on the body in the slow myotomal muscle of rainbow trout Oncorhynchus mykiss using sonomicrometry and electromyography. Strain was independent of tailbeat frequency over the range studied and increased significantly from +/-3.3 % l0 at 0.35BL to +/-6 % at 0.65BL, where l0 is muscle resting length and BL is total body length. Muscle activation occurred significantly later in the strain cycle at 0.35BL (phase shift 59 degrees) than at 0.65BL (30 degrees), and the duration of activity was significantly longer (211 degrees at 0.35BL and 181 degrees at 0.65BL). These results differ from those of previous studies. The results have been used to simulate in vivo activity in isolated muscle preparations using the work loop technique. Preparations from all three locations generated net positive power under in vivo conditions, but the negative power component increased from head to tail. Both kinematically, and in the way its muscle functions to generate hydrodynamic thrust, the rainbow trout appears to be intermediate between anguilliform swimmers such as the eel, which generate thrust along their entire body length, and carangiform fish (e.g. saithe Pollachius virens), which generate thrust primarily at the tail blade.

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FP 13 Immunotoxicity of cadmium, zinc and mercury after in vivo exposure, alone or in mixture in rainbow trout (Oncorhynchus mykiss)

Developmental & Comparative Immunology ◽

10.1016/s0145-305x(97)88594-1 ◽

1997 ◽

Vol 21 (2) ◽

pp. 133 ◽

Cited By ~ 6

Author(s):

J. Sanchez-Dardon ◽

I. Voccia ◽

A. Hontela ◽

P. Anderson ◽

P. Brousseau ◽

...

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Cadmium Zinc

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