scholarly journals Effect of burst swimming and adrenaline infusion on O2 consumption and CO2 excretion in rainbow trout, Salmo gairdneri

1987 ◽  
Vol 131 (1) ◽  
pp. 427-434
Author(s):  
J. F. Steffensen ◽  
B. L. Tufts ◽  
D. J. Randall
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Rainbow Trout ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Respiratory Exchange Ratio ◽  
Salmo Gairdneri ◽  
Adrenaline Infusion ◽  
Burst Swimming ◽  
Co2 Excretion

1. Immediately following burst swimming, the oxygen consumption of rainbow trout increased by 71%, carbon dioxide excretion by 104% and the respiratory exchange ratio by 17%. 80 min after burst swimming all of these parameters had returned to levels which were not significantly different from control values. 2. Infusion of adrenaline into resting fish had no significant effect on oxygen consumption or carbon dioxide excretion and therefore there was no significant change in the respiratory exchange ratio. 3. This infusion of adrenaline caused a significant elevation in the red blood cell pH which was still present 80 min later. 4. The present results contrast with those of van den Thillart, Randall & Lin (1983), who demonstrated carbon dioxide retention after burst swimming. While it is possible that catecholamines may inhibit bicarbonate flux through the red blood cell, our experiments indicate that this inhibition would not result in detectable changes in carbon dioxide excretion or, therefore, in the respiratory exchange ratio.

scholarly journals The pattern of carbon dioxide excretion in the rainbow trout Salmo gairdneri

1978 ◽  
Vol 72 (1) ◽  
pp. 17-24
Author(s):  
M. S. Haswell ◽  
D. J. Randall
Keyword(s):  
Carbon Dioxide ◽  
Rainbow Trout ◽  
Carbonic Anhydrase ◽  
Severe Anaemia ◽  
Salmo Gairdneri ◽  
Gill Epithelium ◽  
Acid Base ◽  
Plasma Bicarbonate ◽  
O2 Delivery ◽  
Co2 Excretion

1. Patterns of carbon dioxide excretion were investigated in rainbow trout (Salmo gairdneri). 2. The loss of erythrocytic carbonic anhydrase caused by severe anaemia does not affect acid/base regulation or the ability of fish to excrete CO2. 3. Bicarbonate excretion across the saline-perfused gills of trout is significant even though residence time for the saline in the gills is only 1--3 s. CO2 excretion across these saline-perfused gills is blocked by the carbonic anhydrase inhibitor, diamox. 4. The excretion of CO2 in fish is via the movement of plasma bicarbonate into the gill epithelium where branchial carbonic anhydrase catalyses the production of CO2. Fish can adjust pH by regulating bicarbonate movement across the gills. 5. The erythrocytic carbonic anhydrase is not necessary for CO2 excretion in the gills but is involved in facilitating Bohr and Root shifts to augment O2 delivery in the tissues.

scholarly journals Adrenergic inhibition of carbon dioxide excretion by trout red blood cells in vitro is mediated by activation of Na+/H+ exchange

1991 ◽  
Vol 157 (1) ◽  
pp. 367-380
Author(s):  
S. F. Perry ◽  
C. M. Wood ◽  
S. Thomas ◽  
P. J. Walsh
Keyword(s):  
Carbon Dioxide ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Beta Adrenoceptor ◽  
Alpha Adrenoceptor ◽  
Adrenoceptor Antagonist ◽  
Exchange Inhibitor ◽  
Adrenoceptor Agonist ◽  
Co2 Excretion

We have used a sensitive new technique to assess the mechanism(s) of adrenergic inhibition of rainbow trout (Oncorhynchus mykiss) red blood cell (RBC) carbon dioxide excretion in vitro. The effect was only apparent using blood acidified to simulate metabolic acidosis. Red blood cell CO2 excretion was inhibited in a dose-dependent manner by physiologically relevant concentrations of noradrenaline (10–1000 nmol l-1) or adrenaline (100–1000 nmol l-1). The beta-adrenoceptor antagonist propranolol abolished the inhibitory effect of adrenaline, whereas the alpha-adrenoceptor antagonist phentolamine was without effect. The action of noradrenaline on RBC CO2 excretion was mimicked by the beta-adrenoceptor agonist isoproterenol, but not by the alpha-adrenoceptor agonist phenylephrine. Therefore, adrenergic inhibition of CO2 excretion is mediated by RBC beta-adrenoceptors, presumably of the beta 1 subtype. The Na+/H+ exchange inhibitor amiloride effectively blocked adrenergic stimulation of Na+/H+ exchange (as indicated from measurements of pHe and RBC pHi) and entirely prevented the inhibition of CO2 excretion. Noradrenaline significantly reduced the rate of CO2 excretion even in the presence of the Cl-/HCO3- exchange inhibitor SITS. Therefore, adrenergic inhibition of CO2 excretion is accomplished via activation of RBC Na+/H+ exchange rather than by a direct inhibition of Cl-/HCO3- exchange. The observed relationship between CO2 excretion rates and the RBC transmembrane pH difference (pHe-pHi) and the occurrence of the inhibition only at low pHe provide further evidence of the linkage with RBC Na+/H+ exchange. We suggest that adrenergic activation of RBC Na+/H+ exchange impedes CO2 excretion by causing a rise in intracellular HCO3- levels concurrent with a reduction of intracellular PCO2. The net result is a reduced gradient for HCO3- entry into the RBC in conjunction with a diminution of the outwardly directed PCO2 gradient. Thus, the rate of formation of CO2 from the dehydration of plasma HCO3- is reduced and, in turn, a portion of this CO2 is not excreted but recycled through the red blood cell.

scholarly journals Acute and chronic influence of temperature on red blood cell anion exchange

2001 ◽  
Vol 204 (1) ◽  
pp. 39-45 ◽  
Author(s):  
F.B. Jensen ◽  
T. Wang ◽  
J. Brahm
Keyword(s):  
Rainbow Trout ◽  
Blood Cell ◽  
Anion Exchange ◽  
Temperature Sensitivity ◽  
Red Blood Cell ◽  
Temperature Acclimation ◽  
Freshwater Turtle ◽  
Acclimation Temperature ◽  
Published Data ◽  
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.

scholarly journals Desensitization of Adrenaline-Induced Red Blood Cell H+ Extrusion in Vitro After Chronic Exposure of Rainbow Trout to Moderate Environmental Hypoxia

1991 ◽  
Vol 156 (1) ◽  
pp. 233-248 ◽  
Author(s):  
S. THOMAS ◽  
R. KINKEAD ◽  
P. J. WALSH ◽  
C. M. WOOD ◽  
S. F. PERRY
Keyword(s):  
Rainbow Trout ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Whole Blood ◽  
Inverse Correlation ◽  
Adrenergic Stimulation ◽  
Plasma Adrenaline ◽  
Arterial Blood Gas ◽  
Arterial Blood

The sensitivity of red blood cell Na+/H+ exchange to exogenous adrenaline was assessed in vitro using blood withdrawn from catheterized rainbow trout (Oncorhynchus mykiss) maintained under normoxic conditions [water PO2, (PwO2)=20.66 kPa] or after exposure to moderate hypoxia (PwO2=6.67-9.33 kPa) for 48 h, which chronically elevated plasma adrenaline, but not noradrenaline, levels. Peak changes in whole-blood extracellular pH over a 30 min period after adding 50–1000 nmoll−1 adrenaline were employed as an index of sensitivity; the blood was pre-equilibrated to simulate arterial blood gas tensions in severely hypoxic fish (PaO2=2.0 kPa, PaCO2=0.31 kPa). Blood pooled from normoxic fish displayed a dose-dependent reduction in whole-blood pH after addition of adrenaline. Blood pooled from three separate groups of hypoxic fish, however, displayed diminished sensitivity to adrenaline, ranging from complete desensitization to a 60%reduction of the response. Subsequent experiments performed on blood from individual (i.e. not pooled) normoxic or hypoxic fish demonstrated an inverse correlation between the intensity of H+ extrusion (induced by exogenous adrenaline addition) and endogenous plasma adrenaline levels at the time of blood withdrawal. However, acute increases in plasma adrenaline levels in vitro did not affect the responsiveness of the red blood cell to subsequent adrenergic stimulation. The intensity of H+ extrusion was inversely related to the PaO2in vivo between 2.67 and 10.66 kPa, and directly related to the logarithm of the endogenous plasma adrenaline level. The results suggest that desensitization of Na+/H+ exchange in chronically hypoxic fish is related to persistent elevation of levels of this catecholamine. This desensitization can be reversed in vitro as a function of time, but only when blood is maintained under sufficiently aerobic conditions.

scholarly journals A Comparison of CO2 Excretion IA Spontaneously Ventilating Blood Perfused Trout Preparation and Salineperfused Gill Preparations: Contribution of the Branchial Epithelium and Red Blood Cell

1982 ◽  
Vol 101 (1) ◽  
pp. 47-60 ◽  
Author(s):  
STEVE F. PERRY ◽  
PETER S. DAVIE ◽  
DAVID J. RANDALL
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Coho Salmon ◽  
Disulfonic Acid ◽  
Gill Epithelium ◽  
Rate Limiting Step ◽  
Branchial Epithelium ◽  
Epithelium Cells ◽  
Co2 Excretion

A spontaneously ventilating blood-perfused trout preparation and saline perfused gill preparations were utilized to investigate the role of the erythrocyte and branchial epithelium in CO2 excretion and acid-base regulation. CO, excretion (MCOCO2) in blood-perfused preparations was positively correlated with haematocrit (Hct), and was abolished completely during plasma-perfusion. Elevating HCO3- concentration of input blood from 10 to 25 mM significantly increased MCOCO2. fourfold in blood-perfused preparations as a result of increased entry of HCO into the red blood cell and not into the gill epithelium. Increased HCO3- concentration was without effect in totally saline-perfused coho salmon (Onchorynchus kisutch). The addition of 4-acetamido-4′-wo-thiocyanatostilbene-2, 2 disulfonic acid (SITS; 10−4 M) to input blood significantly reduced MCO, and oxygen uptake (Mg,OO2) in blood-perfused fish due to inhibition of erythrocytic HCO3-exchange. Unlike blood-perfused preparations, no saline-perfused preparation (isolated holobranchs or totally perfused rainbow trout or coho salmon) displayed measureable CO, excretion at physiological Pco and pH. Increased input PCOt in both blood-perfused and saline-perfused preparations significantly increased MCOt due to enhanced branchial diffusion of molecular CO2. It is concluded that the entry of HCO3- into the erythrocyte is the rate-limiting step in CO, excretion and that movement of HCO3- from plasma to gill epithelium cells in no way contributes to overall CO3 elimination. Note: Department of Physiology and Anatomy, Massey University Palmerston North, New Zealand. Pacific Gamefish Foundation, P.O. Box 25115, Honolulu, Hawaii, U.S.A. 96825

Influence of sampling on the interpretation of haematological measurements of rainbow trout, Salmo gairdneri

1983 ◽  
Vol 61 (2) ◽  
pp. 396-402 ◽  
Author(s):  
L. Lowe-Jinde ◽  
A. J. Niimi
Keyword(s):  
Rainbow Trout ◽  
Blood Cell ◽  
Haematological Parameters ◽  
Salmo Gairdneri ◽  
Short Time Period ◽  
Time Period ◽  
Differential Cell ◽  
Haemoglobin Content ◽  
Short Time ◽  
Tricaine Methanesulfonate

Haematological parameters of rainbow trout (Salmo gairdneri) were examined to determine if the sampling influenced the measurements. The results indicated that haematocrit values of fish anesthetized with tricaine methanesulfonate (TMS or MS 222) sampled after 5–20 min were significantly higher than of fish sampled within 1 min of capture and anesthesia. No differences were observed among haemoglobin content, erythrocyte, and leucocyte counts or their differential cell ratios over the 20-min period. Haemoglobin content and erythrocyte counts increased significantly with size among the three groups examined. It is suggested that differential blood cell ratios could be used as a reliable haematological index because the ratios appear to be independent of the effects of sampling over a short time period.

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