scholarly journals Fish maintain tissue pH despite CO2 blast

2020 ◽  
Vol 223 (7) ◽  
pp. jeb224543
Author(s):  
Kathryn Knight
Keyword(s):  
Tissue Ph

Separation of carotid body chemoreceptor responses to O2 and CO2 by oligomycin and by antimycin A

1982 ◽  
Vol 242 (3) ◽  
pp. C200-C206 ◽  
Author(s):  
E. Mulligan ◽  
S. Lahiri
Keyword(s):  
Steady State ◽  
Carbonic Anhydrase ◽  
Partial Pressure ◽  
Carotid Body ◽  
Body Tissue ◽  
Antimycin A ◽  
Tissue Ph ◽  
Co2 Partial Pressure ◽  
O2 Partial Pressure ◽  
Metabolic Hypothesis

The cat carotid chemoreceptor O2 and CO2 responses can be separated by oligomycin and by antimycin A. Both of these agents greatly diminish or abolish the chemoreceptor O2 response but not the nicotine or CO2 responses. After either oligomycin or antimycin, the responses to increases and decreases in arterial CO2 partial pressure (PaCO2) consisted of increases and decreases in activity characterized respectively by exaggerated overshoots and undershoots. These were eliminated by the carbonic anhydrase inhibitor, acetazolamide, suggesting that they resulted from changes in carotid body tissue pH. The steady-state PaCO2 response remaining after oligomycin was no longer dependent on arterial O2 partial pressure (PaO2). All effects of antimycin were readily reversible in about 20 min. The separation of the responses to O2 and CO2 indicates that there may be at least partially separate pathways of chemoreception for these two stimuli. The similarity of the oligomycin and antimycin results supports the metabolic hypothesis of chemoreception.

The relationship between the unmodified initial tissue pH of human tumours and the response to combined radiotherapy and local hyperthermia treatment

1989 ◽  
Vol 25 (1) ◽  
pp. 73-78 ◽  
Author(s):  
Adriaan P. Van Den Berg ◽  
Jennifer L. Wike-Hooley ◽  
M. Pia Broekmeyer-Reurink ◽  
Jacoba Van Der Zee ◽  
Hubert S. Reinhold
Keyword(s):  
Hyperthermia Treatment ◽  
Tissue Ph ◽  
Local Hyperthermia ◽  
Human Tumours ◽  
The Relationship

ATP depletion and mitochondrial functional loss during ischemia in slow and fast heart-rate hearts

1990 ◽  
Vol 259 (6) ◽  
pp. H1759-H1766 ◽  
Author(s):  
W. Rouslin ◽  
C. W. Broge ◽  
I. L. Grupp
Keyword(s):  
Mitochondrial Function ◽  
Atp Depletion ◽  
Mitochondrial Atpase ◽  
Small Contribution ◽  
Bicarbonate Buffer ◽  
Tissue Ph ◽  
Atp Production ◽  
Dog Heart ◽  
Rat Hearts

In the present study, isolated dog and rat hearts were perfused in the Langendorff mode with Krebs bicarbonate buffer in the absence and presence of 10(-5) M oligomycin. The perfusion protocols employed allowed tissue pH to drop during subsequent ischemic incubations essentially as it would in blood-perfused hearts. Tissue pH, ATP, lactate, and mitochondrial respiratory function were measured during the course of subsequent zero-flow ischemic incubations. The adenosinetriphosphatase (ATPase) activities attributable to both mitochondrial and nonmitochondrial ATPases in sonicated heart homogenates and the actomyosin ATPase in isolated cardiac myofibrils were measured in both species. Consistent with earlier results with a different model in which tissue pH was buffered during the ischemic incubations [W. Rouslin, J. L. Erickson, and R. J. Solaro. Am. J. Physiol. 250 (Heart Circ. Physiol. 19): H503-H508, 1986], the inhibition of the mitochondrial ATPase in situ by oligomycin markedly slowed both tissue ATP depletion and the loss of mitochondrial function during ischemia in the dog. However, oligomycin had only a very small and transient effect on ATP depletion and mitochondrial function in the rat. This was apparently so because of the fivefold higher rate of glycolytic ATP production as well as the nearly threefold higher total nonmitochondrial ATPase activity of ischemic rat compared with ischemic dog heart. These results suggest that although the inhibition of the mitochondrial ATPase makes a major contribution to ATP conservation in ischemic dog heart, it makes only a very small contribution in rat.

scholarly journals NMR Imaging of the Apparent Diffusion Coefficient (ADC) for the Evaluation of Metabolic Suppression and Recovery after Prolonged Cerebral Ischemia

1994 ◽  
Vol 14 (5) ◽  
pp. 723-731 ◽  
Author(s):  
Konstantin-Alexander Hossmann ◽  
Matthias Fischer ◽  
Kurt Bockhorst ◽  
Mathias Hoehn-Berlage
Keyword(s):  
Diffusion Coefficient ◽  
Apparent Diffusion Coefficient ◽  
Extracellular Volume ◽  
Induced Hypotension ◽  
Tissue Ph ◽  
Close Relationship ◽  
Apparent Diffusion ◽  
Internal Mammary ◽  
Systemic Variables ◽  
Postischemic Recovery

Adult normothermic cats were submitted to 1-h complete cerebrocirculatory arrest by intrathoracic occlusion of the internal mammary, the innominate, and the subclavian arteries in combination with pharmacologically induced hypotension. After ischemia, recirculation was initiated at different blood pressure levels to manipulate the postischemia resuscitation conditions. The resulting spectrum of postischemic recovery was studied by combining nuclear magnetic resonance imaging of the apparent diffusion coefficient (ADC) with pictorial assays of brain tissue pH, ATP, glucose, and lactate. Before ischemia, the mean ADC (average of seven coronal slices of five cats) was 713 ± 40 × 10−6 mm2/s. After 10-min ischemia, ADC declined to 68% of control and after 50 min slightly further to 63% of control. During recirculation after 1-h ischemia, recovery of ADC varied depending on the initial reperfusion pressure and other systemic variables. In two animals ADC only transiently increased followed by a secondary decline below the postischemic level. In three other animals ADC returned to near control within 1 h of recirculation. The comparison of ADC changes with previously reported changes in extracellular volume revealed a close relationship, supporting the notion that ADC is a function of the intra/extracellular water compartmentation. Recovery of ADC correlated closely with tissue pH and metabolic recovery, studied 3 h after the initiation of recirculation. Animals without recovery of ADC exhibited global depletion of ATP and glucose and severe lactacidosis, whereas animals with recovery of ADC showed replenishment of ATP and glucose to near control and a substantial reversal of lactacidosis. Our data demonstrate that imaging of ADC provides reliable information about the metabolic state of the brain and can be used to monitor, with high temporal and regional resolution, the manifestation and reversal of ischemic brain injury.

28. Continuous measurement of tissue pH in the human fetus

1978 ◽  
Vol 226 (1-2) ◽  
pp. 183-189 ◽  
Author(s):  
R. Boos ◽  
H. Rüttgers ◽  
D. Muliawan ◽  
D. Heinrich ◽  
F. Kubli
Keyword(s):  
Human Fetus ◽  
Continuous Measurement ◽  
Tissue Ph

Tissue pH changes in renal preservation

1982 ◽  
pp. 109-112 ◽  
Author(s):  
P. Sehr ◽  
P. Bore ◽  
K. Thulborn ◽  
I. Papatheofanis ◽  
L. Chan ◽  
...  
Keyword(s):  
Tissue Ph ◽  
Ph Changes

Percutaneous monitoring of tissue pH with a polymer membrane pH transducer

1986 ◽  
pp. 227-234
Author(s):  
John B Das ◽  
Indira D Joshi ◽  
N C Joseph Lai ◽  
Arvin I Philippart
Keyword(s):  
Polymer Membrane ◽  
Tissue Ph
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