Role of adrenergic-dependent H+ release from red cells in acidosis induced by hypoxia in trout

1987 ◽  
Vol 252 (2) ◽  
pp. R269-R275 ◽  
Author(s):  
B. Fievet ◽  
R. Motais ◽  
S. Thomas
Keyword(s):  
Blood Lactate ◽  
Beta Blocker ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Second Phase ◽  
Beta Adrenergic ◽  
Blood Ph ◽  
Adrenergic Control ◽  
Net Uptake

The response to severe hypoxia is characterized in trout by a sudden drop in blood pH, which is of metabolic origin, and by an increase in the blood concentration of adrenaline. This acidification is biphasic in nature. The first phase of acidification is not associated with a rise in the blood lactate concentration and no longer occurs after pretreatment of the fish with a beta-blocker agent, propranolol. Thus an acid other than lactic acid is released into the blood at the onset of hypoxia and this release, which is under beta-adrenergic control, is responsible for the first phase of acidification. On the other hand the second phase of acidification is related to an increase in blood lactate and is not modified by a beta-blocker agent. We have also demonstrated that deep hypoxia promotes a rapid increase in red blood cell volume and that this cell enlargement is coincident with a large net uptake of Na+ and Cl-. In the presence of beta-blocking agents the Na+ uptake is blocked and the swelling of the cells is considerably inhibited. The residual swelling is clearly due to the chloride shift induced by both deoxygenation of hemoglobin and change in blood pH. In the light of data obtained in vitro on the effect of catecholamines on trout erythrocytes, it can be considered that the first phase of acidification occurring at the onset of hypoxia, and that is under beta-adrenergic control, is due essentially to the release of H+ by red blood cells in exchange with external sodium mediated by a beta-adrenergic-stimulated Na+-H+ exchanger.(ABSTRACT TRUNCATED AT 250 WORDS)

Net lactate uptake during progressive steady-level contractions in canine skeletal muscle

1991 ◽  
Vol 71 (2) ◽  
pp. 514-520 ◽  
Author(s):  
L. B. Gladden
Keyword(s):  
Skeletal Muscle ◽  
Lactic Acid ◽  
Metabolic Rate ◽  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Steady Level ◽  
Net Uptake ◽  
Anesthetized Dogs ◽  
Lactate Uptake

The purpose of this study was to determine the changes in net lactate uptake (L) by skeletal muscle with a constant elevated blood lactate concentration during steady-level contractions of increasing intensity. The gastrocnemius-plantaris muscle group was isolated in situ in 11 anesthetized dogs. An infusion of lactate/lactic acid at a pH of 3.5–3.7 established a blood lactate concentration of approximately 9 mM while maintaining normal blood gas/pH status. L was measured during three consecutive 30-min periods during which the muscles 1) rested, 2) contracted at 1 Hz, and 3) contracted at 4 Hz. L was always positive, indicating net uptake throughout the lactate/lactic acid infusion. Steady-level O2 uptake averaged 10.9 +/- 2.2 ml.kg-1.min-1 (0.49 +/- 0.10 mmol.kg-1.min-1) at rest, 39.3 +/- 2.1 (1.75 +/- 0.09) at 1 Hz, and 127.8 +/- 9.2 (5.70 +/- 0.41) at 4 Hz. Steady-level L increased with the metabolic rate from 0.113 +/- 0.058 mmol.kg-1.min-1 at rest to 0.329 +/- 0.026 at 1 Hz and 0.715 +/- 0.108 at 4 Hz. The increase in L from rest to 1 Hz was accomplished mainly by an increase in arteriovenous lactate difference, whereas the increase from 1 to 4 Hz was entirely due to a large increase in blood flow. These results support the idea that skeletal muscle is not simply a producer of lactate but can be a significant consumer of lactate even during contractions with a large elevation in metabolic rate.

Increase in Serum Ionized Calcium during Exercise

1977 ◽  
Vol 53 (6) ◽  
pp. 579-586 ◽  
Author(s):  
S. Pors Nielsen ◽  
T. Falch Christiansen ◽  
O. Hartling ◽  
J. Trap-Jensen
Keyword(s):  
Blood Lactate ◽  
Venous Blood ◽  
Recovery Period ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Normal Subjects ◽  
Ionized Calcium ◽  
Serum Ionized Calcium

1. Normal subjects showed an average increase in serum ionized calcium (Ca2+) concentration of 0·11 mmol/l in peripheral venous blood 10 min after onset of bicycle exercise at 70% of maximum aerobic capacity. The corresponding mean rise in serum total calcium concentration was 0·21 mmol/l. 2. The change in serum Ca2+ as result of acidification was studied in 20 normal subjects by carbon dioxide equilibration in vitro followed by measurement of serum Ca2+. The log serum Ca2+ was inversely proportional to serum pH. 3. The Δlog serum Ca2+/ΔpH in vitro was similar to the Δlog serum Caa+/ΔpH in vivo during exercise, this ratio, however, being somewhat greater during the first minute of exercise. 4. Serum Ca2+ returned to normal values about 20 min after stopping exercise as the pH returned to normal, but the fall immediately after stopping exercise was more pronounced than that due to the change in pH, as predicted from the studies in vitro. 5. Blood lactate concentration rose from 0·86 to 8·41 mmol/l after 10 min exercise, but the rise in blood lactate during exercise was slower than the rise in serum Ca2+. Also the fall during the recovery period was delayed compared with the fall in serum Ca2+. 6. It is suggested that the rise in serum Ca2+ during severe muscular exercise might be important for the physiological adaptations during work, and for bone metabolism.

Acid-base imbalance in lizards during activity and recovery

1982 ◽  
Vol 98 (1) ◽  
pp. 439-453
Author(s):  
T. T. Gleeson ◽  
A. F. Bennett
Keyword(s):  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Hydrogen Ion ◽  
Acid Base ◽  
Vo2 Max ◽  
Lizard Species ◽  
Arterial Blood ◽  
Blood Ph ◽  
Varanus Salvator

1. The effects of treadmill exercise on oxygen consumption (V02), carbon dioxide production (VCO2), arterial blood lactate concentration ([L-]a), arterial blood pH and arterial gas tensions (PaO2 and PaCO2) were measured in 3 species of lizards (Varanus salvator, V. exanthematicus, Iguana iguana) 2. Varanus salvator was exercised 45 min at an intensity which required 85% of its VO2 max. V. salvator utilized supplementary anaerobic metabolism during the first 10 min of this sustainable exercise, as evidenced by a 16 mmol/l increase in [L-]a. Respiratory exchange ratios (R, where R = VCO2/VO2) exceeded 1.2 when [L-]a and [H+]a were maximal. One half of the accumulated lactate was removed from the blood during the remainder of the 45 min exercise period, while blood pH returned to resting levels. 3. In a second set of experiments, high intensity exercise led to exhaustion after 5 to 10 min in all three species, resulting in large lactate (+ delta[L-]a = 14-20 mmol/l) and hydrogen ion (+ delta[H+]a = 23-57 nmol/l) accumulations. R values ranged from 1.2-1.8 at exhaustion. 4. Recovery from both sustainable and non-sustainable exercise was characterized as a period of rapid lactate removal. Respiratory exchange ratios were low (0.3-0.5) as metabolic CO2 was retained, replacing depleted bicarbonate stores. 5. We conclude that all three lizard species make ventilatory adjustments during and after exercise that minimize disturbances to resting hydrogen ion concentrations and acid-base balance. Varanus salvator demonstrate the ability to re-establish resting acid-base status during sustained exercise requiring 85% of their VO2,max. Changes in R appear to be a useful noninvasive indicator of net blood lactate accumulation.

The influence of execution speed on blood lactate concentration in strength training protocol in bench press exercise

2020 ◽  
Vol 19 (1) ◽  
pp. 32
Author(s):  
Gustavo Taques Marczynski ◽  
Luís Carlos Zattar Coelho ◽  
Leonardo Emmanuel De Medeiros Lima ◽  
Rodrigo Pereira Da Silva ◽  
Dilmar Pinto Guedes Jr ◽  
...  
Keyword(s):  
Strength Training ◽  
Blood Lactate ◽  
Bench Press ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
The Third ◽  
Fast Speed ◽  
Work Volume ◽  
Execution Speed ◽  
Training Protocol

The aim of this study was to analyze the influence of two velocities of execution relative to blood lactate concentration in strength training exercise until the momentary concentric failure. Fifteen men (29.1 ± 5.9 years), trained, participated in the experiment. The volunteers performed three bench press sessions, with an interval of 48 hours between them. At the first session, individuals determined loads through the 10-12 RMs test. In the following two sessions, three series with 90 seconds of interval were performed, in the second session slow execution speed (cadence 3030) and later in the third session fast speed (cadence 1010). For statistical analysis, the Student-T test was used for an independent sample study and considered the value of probability (p) ≤ 0.05 statistically significant. By comparing the number of repetitions and time under tension of the two runs, all series compared to the first presented significant reductions (p < 0.05). The total work volume was higher with the fast speed (p < 0.05). The study revealed that rapid velocities (cadence 1010) present a higher concentration of blood lactate when compared to slow runs (cadence 3030). The blood lactate concentration, in maximum repetitions, is affected by the speed of execution.Keywords: resistance training, cadence, blood lactate.

Effects of cocaine on incremental treadmill exercise in horses

1993 ◽  
Vol 75 (6) ◽  
pp. 2727-2733 ◽  
Author(s):  
K. H. McKeever ◽  
K. W. Hinchcliff ◽  
D. F. Gerken ◽  
R. A. Sams
Keyword(s):  
Right Ventricular ◽  
Blood Lactate ◽  
Venous Blood ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Ventricular Pressure ◽  
Mixed Venous Blood ◽  
Work Intensity ◽  
Venous Blood Lactate ◽  
Mixed Venous

Four mature horses were used to test the effects of two doses (50 and 200 mg) of intravenously administered cocaine on hemodynamics and selected indexes of performance [maximal heart rate (HRmax), treadmill velocity at HRmax, treadmill velocity needed to produce a blood lactate concentration of 4 mmol/l, maximal mixed venous blood lactate concentration, maximal treadmill work intensity, and test duration] measured during an incremental treadmill test. Both doses of cocaine increased HRmax approximately 7% (P < 0.05). Mean arterial pressure was 30 mmHg greater (P < 0.05) during the 4- to 7-m/s steps of the exercise test in the 200-mg trial. Neither dose of cocaine had an effect on the responses to exertion of right atrial pressure, right ventricular pressure, or maximal change in right ventricular pressure over time. Maximal mixed venous blood lactate concentration increased 41% (P < 0.05) with the 50-mg dose and 75% (P < 0.05) with the 200-mg dose during exercise. Administration of cocaine resulted in decreases (P < 0.05) in the treadmill velocity needed to produce a blood lactate concentration of 4 mmol/l from 6.9 +/- 0.5 and 6.8 +/- 0.9 m/s during the control trials to 4.4 +/- 0.1 m/s during the 200-mg cocaine trial. Cocaine did not alter maximal treadmill work intensity (P > 0.05); however, time to exhaustion increased by approximately 92 s (15%; P < 0.05) during the 200-mg trial.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Peripheral Modulators of the Central Fatigue Development and Their Relationship with Athletic Performance in Jumper Horses

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 743
Author(s):  
Francesca Arfuso ◽  
Claudia Giannetto ◽  
Elisabetta Giudice ◽  
Francesco Fazio ◽  
Michele Panzera ◽  
...  
Keyword(s):  
Blood Lactate ◽  
Athletic Performance ◽  
Lactate Concentration ◽  
Indirect Evidence ◽  
Blood Lactate Concentration ◽  
Central Fatigue ◽  
Serotoninergic System ◽  
Stressful Situation ◽  
Passive Behavior ◽  
Fatigue Development

The current study aimed to investigate whether peripheral modulators of serotoninergic function and neurohumoral factors’ changes in athletic horses during an official jumping competition, and to evaluate their relationship with the physical performance of competing horses. From 7 Italian Saddle mares (6–9 years; mean body weight 440 ± 15 kg), performing the same standardized warm-up and jumping course during an official class, heart rate (HR) was monitored throughout the competition. Rectal temperature (RT) measurement, blood lactate and glucose concentration, serum tryptophan, leucine, valine, the tryptophan/branched-chain amino-acids ratio (Try/BCAAs), dopamine, prolactin, and non-esterified fatty acids (NEFAs) were assessed before the exercise event (T0), at the end of the competition stage (5 min ± 10 s following the cessation of the exercise, TPOST5), and 30 min after the end of competition (TPOST30). Highest HR values were recorded during the course and at the outbound (p < 0.0001); blood lactate concentration and RT increased after exercise with respect to the rest condition (p < 0.0001). Lower leucine and valine levels (p < 0.01), and higher tryptophan, Try/BCAAs ratio, and NEFAs values were found at TPOST5 and TPOST30 with respect to T0 (p < 0.0001). A higher prolactin concentration was found at TPOST5 and TPOST30 compared to T0 (p < 0.0001), whereas dopamine showed decreased values after exercise compared to rest (p < 0.0001). Statistically significant correlations among the peripheral indices of serotoninergic function, neurohumoral factors, and athletic performance parameters were found throughout the monitoring period. The findings provide indirect evidence that the serotoninergic system may be involved in fatigue during jumper exercise under a stressful situation, such as competition, in which, in addition to physical effort, athletic horses exhibit more passive behavior.

A Comparison of Asynchronous and Synchronous Arm Cranking During the Wingate Test

2011 ◽  
Vol 6 (3) ◽  
pp. 419-426 ◽  
Author(s):  
Dale I. Lovell ◽  
Dale Mason ◽  
Elias Delphinus ◽  
Chris McLellan
Keyword(s):  
Blood Lactate ◽  
Peak Power ◽  
Anaerobic Power ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Wingate Test ◽  
Mean Power ◽  
Arm Cranking ◽  
Minimum Power ◽  
Time To Peak

Purpose:The aim of this study was to compare asynchronous (AS Y) arm cranking (cranks at 180° relative to each other) with synchronous (SYN) arm cranking (parallel crank setting) during the 30 s Wingate anaerobic test.Methods:Thirty-two physically active men (aged 22.1 ± 2.4 y) completed two Wingate tests (one ASY and one SYN) separated by 4 d in a randomized counterbalanced order. The Wingate tests were completed on a modified electromagnetically braked cycle ergometer. Performance measures assessed during the two tests include peak power, mean power, minimum power, time to peak power, rate to fatigue and maximum cadence (RPMmax). Blood lactate concentration was also measured before and 5 min after the tests.Results:Peak and mean power (both absolute and relative to body weight) during SYN arm cranking were significantly (p < 0.001) less than during ASY arm cranking. Rate to fatigue and RPMmax were also significantly (p = 0.012) lower during SYN arm cranking compared with ASY arm cranking. No significant difference was found between test conditions for minimum power, time to peak power or blood lactate concentration.Conclusions:These findings demonstrate that ASY arm cranking results in higher peak and mean anaerobic power compared with SYN arm cranking during the Wingate test. Therefore, an ASY arm crank configuration should be used to assess anaerobic power in most individuals although specific population groups may require further testing to determine which crank configuration is most suitable for the Wingate test.

The High-Pull Exercise: A Comparison Between a VersaPulley Flywheel Device and the Free Weight

2017 ◽  
Vol 12 (4) ◽  
pp. 527-532 ◽  
Author(s):  
F. Javier Núñez ◽  
Luis J. Suarez-Arrones ◽  
Paul Cater ◽  
Alberto Mendez-Villanueva
Keyword(s):  
Blood Lactate ◽  
Peak Velocity ◽  
Lactate Concentration ◽  
Training Session ◽  
Blood Lactate Concentration ◽  
Free Weight ◽  
Force Velocity ◽  
S Peak ◽  
Rugby Players ◽  
Eccentric Overload

The aim of this study was to examine the kinematics and kinetics (force, velocity, and acceleration) and blood lactate concentration with the VersaPulley (VP) device in comparison with free-weight (FW) exercise at a similar external load. Fifteen rugby players randomly performed 2 training sessions of 6 sets of 6 repetitions with 20 s of recovery between sets of the high-pull exercise with the VP and the FW. The training sessions were separated by 72 h. Barbell displacement (cm), peak velocity (m/s), peak acceleration (m/s2), mean propulsive velocity (m/s), mean propulsive acceleration (m/s2), propulsive phase (%), and mean and maximal force (N) were continuously recorded during each repetition. Blood lactate concentration was measured after each training session (end) and 3 min and 5 min later. Barbell displacement (+4.8%, small ES), peak velocity (+4.5% small ES), mean propulsive acceleration (+8.8%, small ES), and eccentric force (+26.7, large ES) were substantially higher with VP than with FW. Blood lactate concentration was also greater after the VP exercise (end +32.9%, 3 min later +36%, 5 min later +33.8%; large ES). Maximal concentric force was substantially higher with FW than VP during the 6th set (+6.4%, small ES). In the cohort and exercise investigated in the current study, VP training can be considered an efficient training device to induce an accentuated eccentric overload and augmented metabolic demands (ie, blood lactate concentration).

Sign in / Sign up

Export Citation Format

Share Document