The adrenergic volume changes of immature and mature rainbow trout (Oncorhynchus mykiss) erythrocytes (original) (raw)
Related papers
Journal of Experimental Biology
The mechanism of adrenergic swelling and associated pH changes was investigated in avian (goose) and teleost (striped bass and rainbow trout) erythrocytes. The swelling of goose red cells was probably caused by Na+/K+/Cl− co-transport and consecutive osmotic flow of water into the cell. Goose red cells swelled when exposed to isoproterenol in the presence of elevated extracellular K+, but not at physiological K+ concentrations. The swelling was quantitatively inhibited by furosemide, and by removing Cl− from the incubation medium, but was not affected by DIDS. The isoproterenol-induced swelling of fish erythrocytes may be due to loosely coupled Na+/H+ and Cl−/HCO3− exchanges. Furosemide did not completely inhibit the swelling of striped bass red cells. The cell volume increased even if K+ was completely removed from the incubation medium. In contrast, both DIDS and amiloride treatment, and the removal of Na+ from the incubation medium, inhibited the volume changes. In fish red cells...
Stress and fish, 1981
Austract. A series of experiments was conducted to find out if the swelling of rainbow trout erythrocytes had any influence on the oxygen binding properties of blood. The erythrocytes swelled when the fish were sampled by cardiac puncture, when the fish were subjected to hypoxia at l8°C, and when. in the course of determining the in vivo blood oxygen dissociation curve at 18°C, the ambient 0 2 saturation decreased below 50% for the normoxic fish and below 40% for the hypoxic fish. In hypoxia at 11°C and in the determinations of the in vivo dissociation curves at 8°C the red blood cells did not swell appreciably. The swelling of the erythrocytes leads to a decreased intraerythrocytic ATP concentration. which increases the oxygen affinity of the blood. as indicated by the in vivo oxygen dissociation curves at 18°C. The oxygen affinity increase is probably not caused by a decrease in the formation of ATP-Hb complex, as the ATP/Hb molar ratio did not change, but by an increase in the intraerythrocytic pH. In hypoxia at the low temperatures (8 and 11°C), the oxygen affinity of the blood can be increased by both these mechanisms.
Red blood cells from rainbow trout swell in vitro in an isoosmotic medium upon {jadrenergic stimulation. This response is greater with 5.5 than with 2.5 mM extracellular K.+. The red cells also swell in vivo when the fish are stressed or infused with adrenaline. This in vivo response is blocked by the {j antagonist, propranolol. Simultaneously with the in vitro swelling the intracellular proton concentration decreases and the extracellular level increases: incubation with 5 • 10-' M adrenaline increases intracellular pH by 0.1 units, reflecting a 15% decrease in intraerythrocytic proton concentration. The increase in intracellular pH associated with adrenergic swelling will raise blood oxygen affinity in stress, offsetting detrimental effects of hypoxia and exercise on oxygen loading in the gills.
Fish Physiology and Biochemistry, 1989
The occurrence and pH dependence (pHe 7-8) of the adrenergic red cell responses of two salmonids, trout and whitefish, and a percinid, pikeperch were studied. These are all species that live in well-oxygenated waters. The responses were compared to those of carp, which tolerates oxygen-deficient waters. The adrenergic responses of trout and whitefish red cells were pronounced. In these species red cell swelling ng, the accumulation of sodium and chloride in the cell, and the increase in red cell oxygen content at atmospheric oxygen tension were maximal at pH 7.3. In contrast, pikeperch red cells responded to 13-adrenergic stimulation only at extracellular pH 7 .1. In carp, the adrenergic response, occurring below extracellular pH 7.5, was small as compared to the two salmonids. In each case the onset of the adrenergic response coincided with the onset of the Root effect. The differences in the adrenergic responses between the two salmonids and pikeperch suggest that the occurrence of the adrenergic response is not directly related to the environmental oxygen requirements of the species, but may be linked to the activity pattern.
Aquaculture, 1999
Red blood cells from rainbow trout rely mainly on oxidative phosphorylation to cover the energy demand of processes such as cation transport and protein synthesis. Stimulation of these cells with catecholamines leads to an increase in the intracellular Na q concentration due to adrenergic activation of the erythrocyte Na q -H q exchanger. Adrenergic stimulation also increases red cell oxidative phosphorylation which largely can be ascribed to increased activity of the Na q -K q pump in response to the increase in intracellular Na q concentration. Based on experiments with the Na q -ionophore, monensin, it has been suggested that adrenergic stimulation is a prerequisite for the increase in oxidative ATP-production observed when intracellular Na q is increased. Using washed red blood cells from rainbow trout, the present study examines the role for adrenergic stimulation in the metabolic response when intracellular Na q is elevated. It is Ž y8 y6
The Journal of experimental biology, 1997
The metabolic response of sea bream (Sparus aurata) red blood cells to adrenergic stimulation was determined in normoxia and anoxia. In the presence of oxygen, red blood cells swelled and then recovered their resting volume. Continuous monitoring of oxygen uptake displayed the kinetics of the increase in the oxygen affinity of haemoglobin. Cell volume recovery correlated with an activation of ATP consumption, and the energy equilibrium was restored by increasing the rates of respiration and glycolysis. When the respiratory chain was blocked, adrenergic stimulation increased the rates of ATP consumption and glycolysis of red blood cells. Moreover, adrenergic stimulation of deoxygenated erythrocytes also increased cell volume but did not enhance glycolysis or ATP consumption, and the cells remained swollen. Our results suggest that there is an oxygen-linked signal transducer that activates ATP-consuming processes, provided that the adrenergic stimulation occurs in the presence of oxygen.
Blood volume and red cell space in tissues of the rainbow trout, Salmo gairdneri
Comparative biochemistry and physiology. A, Comparative physiology, 1987
1. Whole body blood volume and red cell space of 22 tissues were measured in unanesthetized rainbow trout at 4, 12, 30, 60, 150 and 240 min after dorsal aortic injection of 51Cr-labeled red blood cells. 2. Apparent blood volume decreased during the initial 30 min after injection and increased thereafter. At 240 min the blood volume was 33.5 +/- 3.1 ml/kg body wt. 3. Tissue red cell space varied as a function of the interval between labeled red cell injection and tissue collection. Red cell space was highest in spleen followed by heart, kidney and liver. Lowest red cell spaces were found in stomach and red and white skeletal muscle. 4. Variability in blood volume and tissue red cell space over time suggests that caution should be exercised in the design of experiments that employ indicator dilution measurements to measure vascular volumes.
Journal of Experimental Biology, 1991
The sensitivity of red blood cell Na+/H+ exchange to exogenous adrenaline was assessed in vitro using blood withdrawn from catheterized rainbow trout (Oncorhynchus my kiss) maintained under normoxic conditions [water or after exposure to moderate hypoxia 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 nmol l−1 adrenaline were employed as an index of sensitivity; the blood was pre-equilibrated to simulate arterial blood gas tensions in severely hypoxic fish . 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 de...