The functional significance of adrenergic pH regulation in fish erythrocytes

1989 ◽  
Vol 67 (1) ◽  
pp. 235-238 ◽  
Author(s):  
Bruce L. Tufts ◽  
D. J. Randall
Keyword(s):  
Carrying Capacity ◽  
Functional Significance ◽  
Oncorhynchus Tshawytscha ◽  
Ph Regulation ◽  
Ph Effect ◽  
Blood Oxygen ◽  
Adrenergic Stimulation ◽  
Root Effect ◽  
Oxygen Carrying Capacity

Experiments were conducted in vitro to determine the presence or absence of an adrenergic pH effect in the erythrocytes of Squalus suckleyi, Raja binoculata, and Oncorhynchus tshawytscha. Adrenergic stimulation significantly increased the erythrocyte pH of Oncorhynchus tshawytscha, but did not significantly affect the erythrocyte pH of Squalus suckleyi or Raja binoculata. The results support the view that the functional significance of adrenergic pH regulation in fish erythrocytes is to offset the reduction in blood oxygen carrying capacity caused by the Root effect.

Variation during breeding in parameters that influence blood oxygen carrying capacity in shearwaters

2000 ◽  
Vol 48 (4) ◽  
pp. 347 ◽  
Author(s):  
Cristina Davey ◽  
Alan Lill ◽  
John Baldwin
Keyword(s):  
Carrying Capacity ◽  
Energy Demand ◽  
Blood Parameters ◽  
Aerobic Metabolism ◽  
Egg Laying ◽  
Main Trend ◽  
Breeding Cycle ◽  
Blood Oxygen ◽  
Pattern Of Variation ◽  
Oxygen Carrying Capacity

Parameters that influence blood oxygen carrying capacity (whole-blood haemoglobin content, haematocrit and red blood cell count) were measured in samples of 30 breeding, adult short-tailed shearwaters (Puffinus tenuirostris) on Phillip Island, Victoria at seven key stages of their reproductive cycle. The aim of the investigation was to determine whether variation in blood oxygen carrying capacity during the birds’ 7-month breeding cycle was correlated with variation in the energy demands they experienced or was an incidental by-product of other physiological changes. All the blood parameters varied significantly during breeding, but the pattern of variation was only partly correlated with the likely pattern of changing energy demand imposed on parents by their schedule of breeding activities. The main trend conceivably related to energy demand was that significantly higher values were recorded for these blood parameters during the nestling stage than earlier in the breeding cycle. This could have reflected the high costs of the very long foraging trips undertaken by parents feeding nestlings, but it could also have occurred in preparation for the long migration undertaken soon after breeding finished. It involved an ~10% increase in blood oxygen carrying capacity above the lowest mean value recorded during the breeding cycle and so other mechanisms must also be employed to achieve the increase in aerobic metabolism likely to be required at this stage. The lack of adjustment of blood oxygen carrying capacity to energy demand early in the breeding cycle suggests that either oxygen delivery was not a rate-limiting process for aerobic metabolism at that time or that delivery was enhanced through other mechanisms. At egg laying, females had a lower haematocrit and erythrocyte count than males, which could be attributable to either estrogenic suppression of erythropoiesis or an increase in osmotic pressure of the blood associated with yolk synthesis. Immature, non-breeding birds attending the colony were of similar mass to adults, but did not show the increase in the parameters determining blood oxygen carrying capacity that occurred in adults later in the breeding cycle. Factors other than changing energy requirements (dehydration, burrow hypoxia and differential responsiveness to capture stress) that might have influenced the pattern of variation in blood oxygen carrying capacity of adults during breeding are discussed.

Hematological Aspects of the Thermoacclimatory Process in the Rainbow Trout, Salmo gairdneri

1967 ◽  
Vol 24 (11) ◽  
pp. 2267-2281 ◽  
Author(s):  
Mary Anne DeWilde ◽  
A. H. Houston
Keyword(s):  
Rainbow Trout ◽  
General Problem ◽  
Carrying Capacity ◽  
Packed Cell Volume ◽  
Salmo Gairdneri ◽  
Blood Oxygen ◽  
Hemoglobin Content ◽  
Oxygen Capacity ◽  
Higher Temperature ◽  
Oxygen Carrying Capacity

The blood oxygen capacity of the rainbow trout has been investigated as a function of thermal acclimation in terms of erythrocyte abundance, packed cell volume, hemoglobin concentrations, and mean erythrocytic volume and hemoglobin content. Fish at the lower acclimation temperatures employed (3, 7 C) were characterized by relatively low erythrocyte counts, hematocrits, and hemoglobin levels. Mean erythrocyte volumes tended to be relatively high, whereas mean erythrocytic hemoglobin content was somewhat below that typical of the higher temperature groups. In general, animals held at intermediate temperatures (11, 14, 17 C) showed significant increases in oxygen-carrying capacity by comparison with cold-acclimated fish. Finally trout at 21 C typically had larger numbers of somewhat smaller red cells, more hemoglobin, and higher levels of hemoglobin per erythrocyte than either the low- or intermediate-temperature fish. Significant differences were observed between summer and fall–winter series of trout, particularly with respect to hemoglobin levels. The results are discussed in relation to the general problem of respiratory thermoadaptation.

Chronic hypoxia and the cerebral circulation

2006 ◽  
Vol 100 (2) ◽  
pp. 725-730 ◽  
Author(s):  
Kui Xu ◽  
Joseph C. LaManna
Keyword(s):  
Blood Flow ◽  
Carrying Capacity ◽  
Hemoglobin Concentration ◽  
Capillary Density ◽  
Hypoxic Exposure ◽  
Blood Oxygen ◽  
Brain Capillary ◽  
Blood Flow Increase ◽  
Time Courses ◽  
Oxygen Carrying Capacity

Exposure to mild hypoxia elicits a characteristic cerebrovascular response in mammals, including humans. Initially, cerebral blood flow (CBF) increases as much as twofold. The blood flow increase is blunted somewhat by a decreasing arterial Pco2 as a result of the hypoxia-induced hyperventilatory response. After a few days, CBF begins to fall back toward baseline levels as the blood oxygen-carrying capacity is increasing due to increasing hemoglobin concentration and packed red cell volume as a result of erythropoietin upregulation. By the end of 2 wk of hypoxic exposure, brain capillary density has increased with resultant decreased intercapillary distances. The relative time courses of these changes suggest that they are adjusted by different control signals and mechanisms. The CBF response appears linked to the blood oxygen-carrying capacity, whereas the hypoxia-induced brain angiogenesis appears to be in response to tissue hypoxia.

scholarly journals Energy metabolism in trout red cells: consequences of adrenergic stimulation in vivo and in vitro

1989 ◽  
Vol 143 (1) ◽  
pp. 133-147 ◽  
Author(s):  
R. A. Ferguson ◽  
B. L. Tufts ◽  
R. G. Boutilier
Keyword(s):  
Ph Regulation ◽  
Red Cells ◽  
Red Cell ◽  
Adrenergic Stimulation ◽  
Beta Adrenergic ◽  
Extracellular Acidosis ◽  
Metabolic Functions ◽  
The Face

beta-Adrenergic stimulation of salmonid red cells results in a rapid decrease (within 5 min) in the nucleotide triphosphate:haemoglobin ratio (NTP:Hb), which is thereafter maintained at a constant level, presumably through increased ATP turnover via matched aerobic metabolism and energy-consuming processes. Addition of the beta-adrenergic agonist isoproterenol to rainbow trout red cells in vitro leads to a rise in intracellular pH (pHi), a corresponding decrease in extracellular pH (pHe) and an increase in red cell oxygen consumption (MO2). Moreover, the extent to which red cell pHi is maintained constant in the face of an acute extracellular acidosis in vitro or in vivo is proportional to the adrenergically stimulated increase in red cell MO2. In the absence of oxygen, these red cells remain capable of pH regulation, but cannot maintain NTP:Hb constant. As a result, membrane and metabolic functions become uncoupled in the stimulated deoxygenated cells.

scholarly journals INFLUENCE OF ORGANIC PHOSPHATES ON THE ROOT EFFECT OF MULTIPLE FISH HAEMOGLOBINS

1990 ◽  
Vol 149 (1) ◽  
pp. 425-437 ◽  
Author(s):  
BERND PELSTER ◽  
ROY E. WEBER
Keyword(s):  
Root Effect ◽  
Organic Phosphates ◽  
High Concentrations ◽  
Ph Range ◽  
Oxygen Carrying Capacity ◽  
Very High ◽  
Vitro Data ◽  
In Vitro Data

The influence of organic phosphates on the reduction in oxygen-carrying capacity at low pH (Root effect) in multiple fish haemoglobins has been analysed spectrophotometrically. In stripped haemolysates of carp, trout and eel, the Root effect in the presence of ATP was manifested below pH7.0. In the absence of phosphates, it was only found in trout haemolysate In the pH range between 8.5 and 6.1 no Root effect could be induced in the cathodic component (Hbl) of either trout or eel haemoglobin, even in the presence of very high concentrations of ATP or GTP. This was also true for component II (Hbll) of trout. The anodic component (HblV) of both species, however, exhibited a strong Root effect potentiated by NTP. At the same NTP/Hb4 concentration ratio, GTP was much more effective than ATP in both species The involvement of different haemoglobin components in the generation of high oxygen tensions in the fish swimbladder is discussed by comparing in vivo Root effect data obtained with an eel swimbladder preparation with in vitro data measured in eel blood and haemoglobin.

Seasonal variation in body mass and blood oxygen carrying capacity of the superb fairy-wren (Malurus cyaneus)

2002 ◽  
Vol 50 (3) ◽  
pp. 313 ◽  
Author(s):  
J. Box ◽  
A. Lill ◽  
J. Baldwin
Keyword(s):  
Body Mass ◽  
Carrying Capacity ◽  
Oxygen Delivery ◽  
Blood Oxygen ◽  
Additional Energy ◽  
Blood Haemoglobin ◽  
Malurus Cyaneus ◽  
Energy Challenge ◽  
Oxygen Carrying Capacity ◽  
Winter Fattening

The responses of small birds to many seasonal energy challenges include enhancement of aspects of aerobic metabolism, sometimes involving an increase in the rate of oxygen delivery to the metabolising tissues. One such mechanism that enhances oxygen delivery seasonally is an increase in blood oxygen carrying capacity. This response is enhanced in birds because of their rapid erythrocyte turnover rate. Some small birds have also evolved winter fattening, which helps them to meet the energy challenge presented by winter conditions. Such adaptations, while well documented for North Temperate birds, have received little attention in birds inhabiting temperate Australia. Over a two-year period, we examined seasonal changes in mass, an approximate indicator of fattening, and the parameters determining blood oxygen carrying capacity in a population of superb fairy-wrens (Malurus cyaneus) in outer Melbourne, Australia. Body mass did not vary significantly seasonally, but haematocrit and whole blood haemoglobin were significantly higher in the breeding season than at other times of year and the erythrocyte count was significantly higher in spring than in autumn. We conclude that the failure of the fairy-wrens to increase mass in winter (i.e. show marked winter fattening) was probably due to the comparative mildness of the climate and to the known fitness costs of fat storage. The significant 18% increase in blood oxygen carrying capacity in spring probably helped the birds to meet the additional energy requirements of breeding, particularly the likely increase in flight activity. However, given the magnitude of the increase, other mechanisms must have been involved in meeting breeding costs. The seasonal peak in blood oxygen carrying capacity did not coincide with the time when moulting was most pronounced.

scholarly journals Simultaneous exposure to nitrate and low pH reduces the blood oxygen-carrying capacity and functional performance of a freshwater fish

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Daniel F Gomez Isaza ◽  
Rebecca L Cramp ◽  
Craig E Franklin
Keyword(s):  
Carrying Capacity ◽  
Functional Performance ◽  
Swimming Performance ◽  
Low Ph ◽  
Blood Oxygen ◽  
Aerobic Scope ◽  
Simultaneous Exposure ◽  
Post Exercise ◽  
Oxygen Carrying Capacity ◽  
Post Exercise Recovery

Abstract Human activities present aquatic species with numerous of environmental challenges, including excessive nutrient pollution (nitrate) and altered pH regimes (freshwater acidification). In isolation, elevated nitrate and acidic pH can lower the blood oxygen-carrying capacity of aquatic species and cause corresponding declines in key functional performance traits such as growth and locomotor capacity. These factors may pose considerable physiological challenges to organisms but little is known about their combined effects. To characterise the energetic and physiological consequences of simultaneous exposure to nitrate and low pH, we exposed spangled perch (Leiopotherapon unicolor) to a combination of nitrate (0, 50 or 100 mg L−1) and pH (pH 7.0 or 4.0) treatments in a factorial experimental design. Blood oxygen-carrying capacity (haemoglobin concentration, methaemoglobin concentrations and oxygen equilibrium curves), aerobic scope and functional performance traits (growth, swimming performance and post-exercise recovery) were assessed after 28 days of exposure. The oxygen-carrying capacity of fish exposed to elevated nitrate (50 and 100 mg L−1) was compromised due to reductions in haematocrit, functional haemoglobin levels and a 3-fold increase in methaemoglobin concentrations. Oxygen uptake was also impeded due to a right shift in oxygen–haemoglobin binding curves of fish exposed to nitrate and pH 4.0 simultaneously. A reduced blood oxygen-carrying capacity translated to a lowered aerobic scope, and the functional performance of fish (growth and swimming performance and increased post-exercise recovery times) was compromised by the combined effects of nitrate and low pH. These results highlight the impacts on aquatic organisms living in environments threatened by excessive nitrate and acidic pH conditions.

Functional Hematology of Ringed Seals (Phoca hispida) in the Canadian Arctic

1975 ◽  
Vol 32 (12) ◽  
pp. 2559-2564 ◽  
Author(s):  
J. R. Geraci ◽  
T. G. Smith
Keyword(s):  
Carrying Capacity ◽  
Canadian Arctic ◽  
White Cell ◽  
Blood Sampling ◽  
Blood Oxygen ◽  
Phoca Hispida ◽  
Ringed Seals ◽  
Oxygen Carrying Capacity ◽  
Very High

Hemograms from 20 netted and 6 shot ringed seals (Phoca hispida) were studied. Changes in red and white cell values in netted seals offer evidence for functioning sympathetic and adrenal–cortical stress pathways. The very high blood oxygen carrying capacity of ringed seals suggests that the animal is capable of deep or sustained dives. A technique for blood sampling from the vertebral "extradural" vein is described.

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