Tissue and Whole-Body Extracellular, Red Blood Cell and Albumin Spaces in the Rainbow Trout as a Function of Time: A Reappraisal of the Volume of the Secondary Circulation (original) (raw)
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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.
Hematocrit in oxygen transport and swimming in rainbow trout ( Oncorhynchus mykiss
Respiration Physiology, 1995
The optimal hematocrit (HCtop t) hypothesis was tested by altering Hct (and arterial blood oxygen content, Cao2) between extreme states of anemia and polycythemia (Hct = 8-55%) in the rainbow trout. Since blood viscosity (r/) effects on cardiac output ((~) and O 2 transport (To2) are likely to be greatest when O 2 demand and Q are maximal, we challenged fish to swim to their critical swimming velocity (Ucrit) in a swim-tunnel respirometer at 13°C and measured maximal oxygen uptake ('Qo2max), maximum (~((~m~), and other cardiovascular variables. In addition, experimental temperature was lowered to 5°C to increase r/.
Short Communication the Spleen in Hypoxic and Exercised Rainbow Trout
1990
The teleost spleen is a discrete organ containing, in addition to erythrocytes sequestered from the circulation, erythropoietic tissue involved in the synthesis of new erythrocytes. In this division into supply and synthesis, there appear to be some species differences. The eel spleen is an erythrocyte reservoir but is not thought to be a major erythropoietic organ (Johansson-Sjobeck, 1979). The splenic mass in goldfish does not change with induced anaemia (Houston etal. 1988). The trout spleen, in contrast, plays an erythropoietic role during anaemia (Lane, 1979), in addition to serving as a store of erythrocytes (Randall and Daxboeck, 1982). Exercise in trout is accompanied by haemoconcentration (Black etal. 1966; Stevens, 1968) and the spleen appears to contribute to elevated circulating haemoglobin levels (Stevens, 1968). Capture stress induced a 25% reduction in spleen haemoglobin concentration, [Hb], in the marine teleost Girella tricuspidata, and splenic histology revealed melano-macrophagic centres and erythropoietic tissue indicative of a major role in erythrocyte destruction and synthesis (Ling, 1984). Neither role can be played by the spleen of the icefish, which lacks haemoglobin (Wells et al. 1990). Although storage and synthesis of erythrocytes in the spleen have been examined in few fish, several intraspecific factors affect the size of the spleen. These include reproductive status and body weight (Yamamoto and Itazawa, 1989), exercise (Yamamoto et al. 1980; Yamamoto, 1988) and hypoxia (Yamamoto et al. 1985; Wells et al. 1989). Active fish appear to have highly contractile spleens that assist in the expulsion of erythrocytes (Nilsson and Grove, 1974). Rainbow trout, more than any other fish, have received the close attention of researchers, and yet we can find little information concerning the possible role of the trout spleen in erythrocyte supply during exercise and hypoxia. Furthermore, no attempt has been made to discern whether erythrocytes stored in the spleen are qualitatively different from those in general circulation. In this study we have addressed these problems. Female rainbow trout (Salmo gairdneri Richardson) were obtained from a
Body fluid volume regulation in elasmobranch fish
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2007
This review addresses an often overlooked aspect of elasmobranch osmoregulation, i.e., control of body fluid volume. More specifically the review addresses the impact of changes in blood volume in elasmobranchs exposed to different environmental salinities. Measurement of blood volume in the European lesser-spotted dogfish, Scyliorhinus canicula, following acute and chronic exposure to 80% and 120% seawater (SW) is reported. In 80%, 100% and 120% SW-adapted S. canicula, blood volume was 6.3 ± 0.2, 5.6 ± 0.2 and 4.6 ± 0.2 mL 100 g − 1 body mass, respectively. Blood volume was significantly higher and lower in 80% and 120% SW-acclimated animals compared to 100% SW controls. Comparisons are made between these results and previously published data. The role of drinking and volume regulation in elasmobranchs is discussed. For the first time measured water reabsorption rates and solute flux rates across the elasmobranch intestinal epithelia are presented. Water reabsorption rates did not differ between 100% SW-adapted bamboo shark, Chiloscyllium plagiosum, and fish acutely transferred to 140% SW. For the most part net solute flux rates and direction for both the 100% and 140% SW groups were the same with the exception of a net efflux of chloride and potassium in the 140% group and influx of these ions in the 100% adapted group. The significance of the intestine as part of the overall elasmobranch osmoregulatory strategy is discussed as is the role of the kidneys, rectal gland and gills in the regulation of body fluid volume in this class of vertebrates.
Journal of Experimental Biology, 2000
In this study, we examined whether the adrenergic volume response of teleost erythrocytes is related to cell maturity. Rainbow trout (Oncorhynchus mykiss) were made anaemic by reducing their haematocrit to approximately 50 % of the original value. After 3–4 weeks, small, young erythrocytes were seen in the circulation. By measuring the volume distribution of blood samples from anaemic fish before and after noradrenaline stimulation (10 min, 10(−5)mol l(−1) final concentration), we were able to show that the volume response of young, immature erythrocytes to catecholamine stimulation was greater than that of mature erythrocytes. In addition, the membrane fluidity, measured using the steady-state fluorescence polarisation method, was greater in anaemic fish after 24 days of recovery from bleeding than in control fish. Since blood from anaemic fish contained a large fraction of immature erythrocytes, this result indicates that the fluidity of the membrane of immature erythrocytes is gr...
Journal of Experimental Biology
The contribution of the secondary circulatory system to acid-base regulation and epithelial ion transport was evaluated qualitatively in freshwater-acclimated rainbow trout. The dorsal aorta (DA) and the lateral cutaneous vessel (LCV) (which is considered to be the venous drainage of the secondary system) were chronically cannulated and the fish were exposed to environmental hypercapnia (2 % CO2) after establishment of normocapnic control values. Fluid sampled from the LCV contained much less haemoglobin (0.14 g 100 ml−1) and fewer blood cells (packed cell volume, PCV, 1.2-1.7%) than DA blood ([Hb] 8.2-8.9 g 100 ml−1, PCV 27.2-32.5%) regardless of ambient CO2 levels, indicating highly limited access of red blood cells to the secondary circulatory system through anastomoses connecting it to the primary system. There was no significant difference between the two sampling sites for any of the acid-base variables (pH, PCO2 [HCO3−]) and most plasma ion concentrations ([Na+], [Ca2+], [Mg2...
Journal of Experimental Biology, 2014
Teleost fishes and mammalian lineages diverged 400 million years ago, and environmental requirements (water versus air) have resulted in marked differences in cardiovascular function between fish and mammals. Suggestions that the fish secondary vascular system (SVS) could be used as a model for the mammalian lymphatic system should be taken with caution. Despite molecular markers indicating similar genetic origin, functions of the SVS in teleost fish are probably different from those of the mammalian lymphatic system. We determined that, in resting glass catfish (Kryptopterus bicirrhis), plasma moves from the primary vascular system (PVS) to the SVS through small connecting vessels less than 10 μm in diameter, smaller than the red blood cells (RBCs). During and following hypoxia or exercise, flow increases and RBCs enter the SVS, possibly via β-adrenoreceptor-mediated dilation of the connecting vessels. The volume of the SVS can be large and, as RBCs flow into the SVS, the haematocrit of the PVS falls by as much as 50% of the resting value. Possible functions of the SVS, including skin respiration, ionic and osmotic buffering, and reductions in heart work and RBC turnover, are discussed.