scholarly journals Hypoxic Acclimation in the Lamprey, Lampetra Fluviatilis: Organismic and Erythrocytic Responses

1984 ◽  
Vol 109 (1) ◽  
pp. 109-119
Author(s):  
MIKKO NIKINMAA ◽  
ROY E. WEBER
Keyword(s):  
Intracellular Ph ◽  
Teleost Fish ◽  
Ventilatory Response ◽  
Red Cells ◽  
O2 Consumption ◽  
Lampetra Fluviatilis ◽  
Freeze Thaw ◽  
Allosteric Interaction ◽  
Acclimatory Response ◽  
Hypoxic Acclimation

Acute exposure of Lampetra fluviatilis to hypoxia (PO2 = 40–50 mmHg) resulted in a large increase in ventilation frequency and a significant increase in O2 consumption (from 40 to 60 mg kg−1h−1 at 8°C). After 1 week's hypoxia, the O2 consumption decreased (from 60 to 50 mg kg−1 h−1), indicating the existence of slow, acclimatory changes that remove some of the strain from the ventilatory response. The hypoxic animals had a higher blood O2 affinity than the normoxic controls. This acclimatory response is not the result of a decreased allosteric interaction between the haemoglobin and erythrocytic organic phosphates, as in teleost fish, but is attributable partly to dilution of haemoglobin within the red cells and partly to an increase in the intracellular pH. The intraerythrocytic pH of hypoxic animals, measured with a freeze-thaw method, was higher than the plasma pH, suggesting that protons are not passively distributed.

Intracellular pH (pHi) of Red Cells Stored in Acid Citrate Dextrose Medium

1975 ◽  
Vol 78 (3) ◽  
pp. 469-474 ◽  
Author(s):  
Sachiko TSUDA ◽  
Akio TOMODA ◽  
Shigeki MINAKAMI
Keyword(s):  
Intracellular Ph ◽  
Red Cells ◽  
Acid Citrate Dextrose ◽  
Citrate Dextrose

Lactic acidosis transiently increases metabolic rate of turtle myocytes

1994 ◽  
Vol 266 (4) ◽  
pp. R1238-R1243 ◽  
Author(s):  
C. L. Watson ◽  
W. L. Few ◽  
G. Panol ◽  
D. C. Jackson
Keyword(s):  
Lactic Acidosis ◽  
Metabolic Rate ◽  
Intracellular Ph ◽  
Ventricular Myocytes ◽  
Ph Regulation ◽  
Ringer Solution ◽  
O2 Consumption ◽  
Free Solution ◽  
Na Pump ◽  
Pump Activity

We measured O2 consumption as an estimate of metabolic rate in isolated calcium-tolerant ventricular myocytes of turtles (Chrysemys picta belli) at control pH 7.8 and in the same solution brought to pH 7.4 and 7.0 with additions of lactic acid. Our aim was to test the hypothesis that lactic acidosis caused metabolic depression by initiating downregulation of Na+ channels, and thus Na(+)-K(+)-ATPase (Na+ pump) activity, which we would measure as a decrease in O2 consumption. Myocyte O2 consumption was measured in reptilian N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid-buffered Ringer solution and in nomially Na(+)- and Ca(2+)-free solution, thus estimating the Na+ pump component of metabolic rate. Lowering extracellular pH from 7.8 to 7.0 resulted in a significant increase in metabolic rate of cells in Ringer solution but not those in Na(+)- and Ca(2+)-free solution. This result was unchanged by the addition of 2 mM Ca2+ to Na(+)-free cell suspensions, indicating that the difference was due to the presence of Na+. Addition of 100 microM amiloride to cells in Ringer solution at pH 7.0 abolished the increase in O2 consumption, suggesting that the apparent increase in Na(+)-K(+)-ATPase activity was secondary to Na(+)-H+ exchange. Intracellular pH was measured using 5,5-dimethyl[14C]oxazolidine-2,4-dione. Cells treated with amiloride and those in Na(+)- and Ca(2+)-free solution did not regulate intracellular pH following acidosis and maintained basal metabolic rate. These data suggest that the Na(+)-H+ exchanger is an important contributor to intracellular pH regulation in the myocyte but increases Na+ pump activity and metabolic rate immediately following acidosis.

Respiratory stimulation by female hormones in awake male rats

1991 ◽  
Vol 71 (1) ◽  
pp. 37-42 ◽  
Author(s):  
K. Tatsumi ◽  
M. Mikami ◽  
T. Kuriyama ◽  
Y. Fukuda
Keyword(s):  
Tidal Volume ◽  
Ventilatory Response ◽  
Blood Gases ◽  
Male Rats ◽  
Co2 Production ◽  
Male Rat ◽  
O2 Consumption ◽  
Estradiol Treatment ◽  
Respiratory Stimulation ◽  
Ventilatory Response To Co2

The respiratory effect of progestin differs among various animal species and humans. The rat does not hyperventilate in response to exogenous progestin. The present study was conducted to determine whether administration of combined progestin and estrogen prompts ventilatory stimulation in the male rat. Ventilation, blood gases, and metabolic rates (O2 consumption and CO2 production) were measured in the awake and unrestrained male Wistar rat. The combined administration of a synthetic potent progestin (TZP4238) and estradiol for 5 days significantly increased tidal volume and minute expiratory ventilation (VE), reduced arterial PCO2, and enhanced the ventilatory response to CO2 inhalation (delta VE/delta PCO2). On the other hand, respiratory frequency, O2 consumption, CO2 production, and body temperature were not affected. The arterial pH increased slightly, with a concomitant decrease in plasma [HCO3-]. Administration of either TZP4238 or estradiol alone or vehicle (Tween 80) had no effect on respiration, blood gases, and ventilatory response to CO2. The results indicated that respiratory stimulation following combined progestin plus estradiol treatment in the male rat involves activation of process(es) that regulate tidal volume and its augmentation during CO2 stimulus.

Human RhAG ammonia channel is impaired by the Phe65Ser mutation in overhydrated stomatocytic red cells

2012 ◽  
Vol 302 (2) ◽  
pp. C419-C428 ◽  
Author(s):  
Sandrine Genetet ◽  
Pierre Ripoche ◽  
Julien Picot ◽  
Sylvain Bigot ◽  
Jean Delaunay ◽  
...  
Keyword(s):  
Intracellular Ph ◽  
Hemolytic Anemia ◽  
Rate Constant ◽  
Rate Constants ◽  
Flow Analysis ◽  
Red Cells ◽  
Stopped Flow ◽  
Loss Of Function ◽  
Dramatic Decrease ◽  
Time Courses

In red cells, Rh-associated glycoprotein (RhAG) acts as an ammonia channel, as demonstrated by stopped-flow analysis of ghost intracellular pH (pHi) changes. Recently, overhydrated hereditary stomatocytosis (OHSt), a rare dominantly inherited hemolytic anemia, was found to be associated with a mutation (Phe65Ser or Ile61Arg) in RHAG. Ghosts from the erythrocytes of four of the OHSt patients with a Phe65Ser mutation were resealed with a pH-sensitive probe and submitted to ammonium gradients. Alkalinization rate constants, reflecting NH3transport through the channel and NH3diffusion unmediated by RhAG, were deduced from time courses of fluorescence changes. After subtraction of the constant value found for Rhnulllacking RhAG, we observed that alkalinization rate constant values decreased ∼50% in OHSt compared with those of controls. Similar RhAG expression levels were found in control and OHSt. Since half of the expressed RhAG in OHSt most probably corresponds to the mutated form of RhAG, as expected from the OHSt heterozygous status, this dramatic decrease can be therefore related to the loss of function of the Phe65Ser-mutated RhAG monomer.

Hamsters vs. rats: metabolic and ventilatory response to development in chronic hypoxia

1994 ◽  
Vol 77 (6) ◽  
pp. 2748-2752 ◽  
Author(s):  
P. B. Frappell ◽  
J. P. Mortola
Keyword(s):  
Metabolic Rate ◽  
Body Mass ◽  
Chronic Hypoxia ◽  
Ventilatory Response ◽  
Acute Hypoxia ◽  
Body Growth ◽  
O2 Consumption ◽  
Ventilatory Parameters ◽  
Surface Dwelling

The postnatal developments of the rat and hamster were compared after the animals were raised from birth for 21 days either in normoxia (control animals) or chronic hypoxia (PO2 of 80–90 Torr). Compared with control rats, hypoxic rats had a reduction in body mass. Hypoxic rats had lowered O2 consumption (VO2) and increased (67%) ventilation (VE), whereas hypoxic hamsters maintained the same metabolic rate as control hamsters but increased VE by 100%. As a result, when raised in hypoxia both species increased VE/VO2 to the same extent. When acutely exposed to hypoxia, control animals of both species increased VE (54–58%) and lowered VO2 (26%). Thus, whether the exposure to hypoxia is acute or chronic, both species hyperventilated (i.e., increased VE/VO2) to approximately the same degree. However, in the rat VO2 decreased similarly in both acute and chronic hypoxia, whereas in the hamster VO2 decreased with acute hypoxia but was maintained under chronic hypoxia. Within 1 day of the animals being returned to normoxia, metabolic and ventilatory parameters of hypoxic animals returned to control values. In conclusion, the semifossorial hamster seems better suited to development in chronic hypoxia than the surface-dwelling rat because by avoiding prolonged hypometabolism it can better maintain body growth.

Luft's syndrome: O2 cost of exercise and chemical control of breathing

1975 ◽  
Vol 39 (5) ◽  
pp. 857-859 ◽  
Author(s):  
N. H. Edelman ◽  
T. V. Santiago ◽  
H. L. Conn
Keyword(s):  
Chemical Control ◽  
Ventilatory Response ◽  
Normal Subjects ◽  
Control Of Breathing ◽  
O2 Consumption ◽  
Arterial Blood ◽  
Skeletal Muscle Mitochondria ◽  
Ventilatory Response To Co2

The oxygen cost of exercise and chemical control of breathing were studied in a subject with Luft's syndrome, a disorder in which skeletal muscle mitochondria have a high “resting” O2 consumption which is imcreased only slightly by stimulation with excess phosphate acceptor, but a normal P/O ratio. The O2 consumption was more than three times normal (1.05 1/min) at rest but could be doubled when stimulated by maximal exercise. The O2 cost of exercise was similar to that of normal subjects. At rest, arterial blood PCO2 and ventilatory response to CO2 were normal, while ventilatory response to hypoxia was four times the predicted value. The data 1) confirm, in vivo, the normal respiratory efficiency of skeletal muscles in this disorder; 2) suggest that in vitro estimates of the extent to which mitochondrial respiration can be stimulated may not correlate with in vivo determinations; and 3) suggests that hypermetabolism per se can cause the ventilatory adjustments which are associated with exercise in normal subjects.

Intracellular pH of red cells stored in acid citrate dextrose medium

1972 ◽  
Vol 28 (12) ◽  
pp. 1481-1482 ◽  
Author(s):  
S. Tsuda ◽  
K. Kakinuma ◽  
S. Minakami
Keyword(s):  
Intracellular Ph ◽  
Red Cells ◽  
Acid Citrate Dextrose ◽  
Citrate Dextrose

Freeze-thaw recovery of AC hemoglobin red cells

Cryobiology ◽  
1981 ◽  
Vol 18 (6) ◽  
pp. 547-549 ◽  
Author(s):  
Lloyd O. Cook ◽  
Dean P. Bonderman ◽  
Mary Lynn Franks
Keyword(s):  
Red Cells ◽  
Freeze Thaw

scholarly journals Adrenergic Swelling of Nucleated Erythrocytes: Cellular Mechanisms in a Bird, Domestic Goose, and two Teleosts, Striped Bass and Rainbow Trout

1984 ◽  
Vol 113 (1) ◽  
pp. 215-224 ◽  
Author(s):  
MIKKO NIKINMAA ◽  
WRAY H. HUESTIS
Keyword(s):  
Rainbow Trout ◽  
Cell Volume ◽  
Intracellular Ph ◽  
Striped Bass ◽  
Incubation Medium ◽  
Red Cells ◽  
Red Cell ◽  
Volume Changes ◽  
Cellular Mechanisms ◽  
Loosely Coupled

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 the swelling is associated with a clear acidification of the medium and alkalinization of the red cell contents. This phenomenon was most pronounced when the cells were treated simultaneously with DIDS and isoproterenol; the intracellular pH became higher than the extracellular one. Both amiloride and removal of Na+ from the incubation medium prevented the reversal of the transmembrane pH gradient in cells treated simultaneously with DIDS and isoproterenol.

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