Effect of prior eccentric contractions on lactate/H+ transport in rat skeletal muscle

1998 ◽  
Vol 274 (3) ◽  
pp. E554-E559 ◽  
Author(s):  
Henriette Pilegaard ◽  
Sven Asp
Keyword(s):  
Skeletal Muscle ◽  
Buffer Capacity ◽  
Ph Regulation ◽  
Eccentric Contractions ◽  
Lactate Transport ◽  
Giant Vesicles ◽  
Muscle Lactate ◽  
Muscle Ph ◽  
Supramaximal Stimulation ◽  
Muscle Types

The effect of prior eccentric contractions on skeletal muscle lactate/H+transport was investigated in rats. Lactate transport was measured in sarcolemmal giant vesicles obtained from soleus and red (RG) and white gastrocnemii (WG) muscles 2 days after intense eccentric contractions (ECC) and from the corresponding contralateral control (CON) muscles. The physiochemical buffer capacity was determined in the three muscle types from both ECC and CON legs. Furthermore, the effect of prior eccentric contractions on release and muscle content of lactate and H+ during and after supramaximal stimulation was examined using the perfused rat hindlimb preparation. The lactate transport rate was lower ( P < 0.05) in vesicles obtained from ECC-WG (29%) and ECC-RG (13%) than in vesicles from the CON muscles. The physiochemical buffer capacity was reduced ( P < 0.05) in ECC-WG (13%) and ECC-RG (9%) compared with the corresponding CON muscles. There were only marginal effects on the soleus muscle. Muscle lactate concentrations and release of lactate during recovery from intense isometric contractions were lower ( P< 0.05) in ECC than in CON hindlimbs, indicating decreased anaerobic glycogenolysis. In conclusion, the sarcolemmal lactate/H+ transport capacity and the physiochemical buffer capacity were reduced in prior eccentrically stimulated WG and RG in rats, suggesting that muscle pH regulation may be impaired after unaccustomed eccentric exercise. In addition, the data indicate that the glycogenolytic potential is decreased in muscles exposed to prior eccentric contractions.

Importance of pH regulation and lactate/H+ transport capacity for work production during supramaximal exercise in humans

2007 ◽  
Vol 102 (5) ◽  
pp. 1936-1944 ◽  
Author(s):  
Laurent Messonnier ◽  
Michael Kristensen ◽  
Carsten Juel ◽  
Christian Denis
Keyword(s):  
Proton Transport ◽  
Buffer Capacity ◽  
Ph Regulation ◽  
Work Capacity ◽  
Monocarboxylate Transporter ◽  
Supramaximal Exercise ◽  
Muscle Lactate ◽  
Muscle Ph ◽  
Work Production ◽  
Exercise In Humans

We examine the influence of the cytosolic and membrane-bound contents of carbonic anhydrase (CA; CAII, CAIII, CAIV, and CAXIV) and the muscle content of proteins involved in lactate and proton transport [monocarboxylate transporter (MCT) 1, MCT4, and Na+/H+ exchanger 1 (NHE1)] on work capacity during supramaximal exercise. Eight healthy, sedentary subjects performed exercises at 120% of the work rate corresponding to maximal oxygen uptake (Ẇmax) until exhaustion in placebo (Con) and metabolic alkalosis (Alk) conditions. The total (Wtot) and supramaximal work performed (Wsup) was measured. Muscle biopsies were obtained before and immediately after standardized exercises (se) at 120% Ẇmax in both conditions to determine the content of the targeted proteins, the decrease in muscle pH (ΔpHm), and the muscle lactate accumulation ([Lac]m) per joule of Wsup (ΔpHm/Wsup-se and Δ[Lac]m/Wsup-se, respectively) and the dynamic buffer capacity. In Con, Wsup was negatively correlated with ΔpHm/Wsup-se, positively correlated with Δ[Lac]m/Wsup-se and MCT1, and tended to be positively correlated with MCT4 and NHE1. CAII + CAIII were correlated positively with ΔpHm/Wsup-se and negatively with Δ[Lac]m/Wsup-se, while CAIV was positively related to Wtot. The changes in Wsup with Alk were correlated positively with those in dynamic buffer capacity and negatively with Wsup in Con. Performance improvement with Alk was greater in subjects having a low content of proteins involved in pH regulation and lactate/proton transport. These results show the importance of pH regulating mechanisms and lactate/proton transport on work capacity and the role of the CA to delay decrease in pHm and accumulation in [Lac]m during supramaximal exercise in humans.

Metabolic changes in skeletal muscle and blood of greyhounds during 800-m track sprint

1988 ◽  
Vol 255 (3) ◽  
pp. R513-R519 ◽  
Author(s):  
G. P. Dobson ◽  
W. S. Parkhouse ◽  
J. M. Weber ◽  
E. Stuttard ◽  
J. Harman ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Vastus Lateralis ◽  
Fold Increase ◽  
Biceps Femoris ◽  
Muscle Lactate ◽  
Muscle Ph ◽  
The Mean ◽  
Metabolic Properties ◽  
Fast Twitch ◽  
Anaerobic Conversion

The aim of this study was to examine some metabolic properties and changes that occur in skeletal muscle and blood of greyhounds after an 800-m sprint. Three prime moving fast-twitch muscles were selected: biceps femoris (BF), gastrocnemius (G), and vastus lateralis (VL). The amount of glycogen utilized during the event was 42.57, 43.86, and 42.73 mumol glucosyl units/g wet wt, respectively. Expressed as a function of race time (48.3 +/- 0.7 s, n = 3), the mean rate of glycogen breakdown was 53.48 +/- 0.5 mumol.g wet wt-1.min-1 during the sprint. This is equivalent to an ATP turnover of 160 mumol.g wet wt-1.min-1, assuming 100% anaerobic conversion to lactate. This represents a conservative estimate, since greyhound muscle is heterogeneous and comprised of a large percentage of fast-twitch oxidative fibers (Armstrong et al., Am. J. Anat. 163: 87-98, 1982). The large decrease in muscle glycogen was accompanied by a 6- to 7-fold increase in muscle lactate from 3.48 +/- 0.13 to 25.42 +/- 3.54 (BF), 2.54 +/- 1.05 to 18.96 +/- 2.60 (G), and 4.57 +/- 0.44 to 30.09 +/- 1.94 mumol.g wet wt (VL), and a fall in muscle pH from 6.88 +/- 0.03 to 6.40 +/- 0.02 (BF), 6.92 +/- 0.02 to 6.56 +/- 0.02 (G), and 6.93 +/- 0.02 to 6.47 +/- 0.01 (VL). Cytosolic phosphorylation potential in BF decreased 10-fold from 11,360 +/- 680 to 1,184 +/- 347, and redox potential decreased 5-fold, indicating a marked reduction in the cytosol at this time.(ABSTRACT TRUNCATED AT 250 WORDS)

Skeletal muscle pH assessed by biochemical and 31P-MRS methods during exercise and recovery in men

1994 ◽  
Vol 77 (5) ◽  
pp. 2194-2200 ◽  
Author(s):  
M. J. Sullivan ◽  
B. Saltin ◽  
R. Negro-Vilar ◽  
B. D. Duscha ◽  
H. C. Charles
Keyword(s):  
Skeletal Muscle ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Normal Subjects ◽  
Peak Exercise ◽  
Resonance Spectroscopy ◽  
Muscle Lactate ◽  
Lactate Accumulation ◽  
31P Mrs ◽  
Muscle Ph

The present study was designed to compare evaluation of skeletal muscle metabolism (vastus lateralis) evaluated by 31P-magnetic resonance spectroscopy (MRS) and biochemical analysis. During identical isometric knee extensor exercise protocols to fatigue in eight men, biopsy samples were taken at rest, peak exercise, and 32 s postexercise and 31P-MRS data were collected continuously for phosphocreatine (PCr), pH, ATP, and P(i) at 8- or 32-s intervals. There was no difference in ATP or pH measurements between the two techniques at rest, during peak exercise, or in recovery. Corresponding measurements of pH by the two techniques were closely related (r = 0.88, P < 0.01), and pH measured by 31P-MRS was closely related to muscle lactate accumulation (r = -0.84, P < 0.001). The level of PCr at peak exercise, expressed as a percentage of the baseline value, was not different between the two techniques (42 +/- 15 vs. 46 +/- 15%). The results indicate that, in skeletal muscle in normal subjects, 1) measurements of pH and PCr at rest and during exercise do not differ between the 31P-MRS and biopsy techniques and 2) muscle pH measured by 31P-MRS is closely related to lactate accumulation in men. Our data suggest that direct comparison of results of studies of exercise metabolism using these two techniques is warranted.

Kinetics of lactate transport in sarcolemmal giant vesicles obtained from human skeletal muscle

1994 ◽  
Vol 76 (3) ◽  
pp. 1031-1036 ◽  
Author(s):  
C. Juel ◽  
S. Kristiansen ◽  
H. Pilegaard ◽  
J. Wojtaszewski ◽  
E. A. Richter
Keyword(s):  
Lactate Concentration ◽  
Low Ph ◽  
Marker Enzyme ◽  
Lactate Transport ◽  
Giant Vesicles ◽  
Biopsy Material ◽  
Muscle Lactate ◽  
Transport Studies ◽  
Equilibrium Exchange ◽  
Vesicular Membrane

We developed a method that allows the measurement of muscle lactate transport in humans. The transport studies were carried out with giant (1.8- to 36-microns-diam) sarcolemmal vesicles obtained by collagenase treatment of needle biopsy material. Marker enzyme analyses demonstrated that the vesicular membrane is predominantly of sarcolemmal origin, contamination with sarcoplasmic reticulum membranes is very low, and mitochondrial membranes are not a major contaminant. The vesicles were loaded with labeled lactate, and the efflux was measured. The system displayed saturation kinetics and inhibitor sensitivity. In equilibrium exchange experiments (pH 7.4, 21 degrees C), the Michaelis-Menten constant (Km) for the carrier-mediated flux was 30 +/- 8 (SD) mM and maximal transport rate (Vmax) was 184 +/- 24 pmol.cm-2.s-1 (142 nmol.mg protein-1.min-1). In zero-trans efflux experiments, Km was 24 +/- 8 mM and Vmax was 81 +/- 11 pmol.cm-2.s-1 (63 nmol.mg protein-1.min-1). In infinite-cis experiments with a variable lactate concentration on the outside of the vesicles, Km was 8 +/- 4 mM and Vmax was 136 +/- 9 pmol.cm-2.s-1 (105 nmol.mg protein-1.min-1). Thus, the system displayed transacceleration. Low pH (6.4) had no significant effect on equilibrium exchange experiments, whereas in zero-trans experiments low pH at the trans side inhibited the flux by 50%. We concluded that lactate transport can be studied in giant vesicles obtained from a single human muscle biopsy. Our data provide evidence for the existence of a lactate carrier in human sarcolemma. This transport system must be taken into account in models of human lactate kinetics.

Effects of Exercise on Lactate Transport Into Mouse Skeletal Muscles

1994 ◽  
Vol 19 (3) ◽  
pp. 275-285 ◽  
Author(s):  
Arend Bonen ◽  
Karl J. A. McCullagh
Keyword(s):  
Skeletal Muscle ◽  
Key Words ◽  
Muscle Glycogen ◽  
Skeletal Muscles ◽  
Treadmill Exercise ◽  
Lactate Transport ◽  
Muscle Lactate ◽  
Slow Twitch ◽  
Fast Twitch

Skeletal muscle lactate transport was investigated in vitro in isolated fast-twitch (EDL) and slow-twitch soleus (Sol) skeletal muscles from control and exercised mice. Exercise (23 m/min, 8% grade) reduced muscle glycogen by 37% in EDL (p < 0.05) and by 35% in Sol muscles (p < 0.05). Lactate transport measurements (45 sec) were performed after 60 min of exercise in intact EDL and Sol muscles in vitro, at differing pH (6.5 and 7.4) and differing lactate concentrations (4 and 30 mM). Lactate transport was observed to be greater in Sol than in EDL (p < 0.05). In the exercised muscles there was a small but significant increase in lactate transport (p < 0.05). Lactate transport was greater when exogenous lactate concentrations were greater (p < 0.05) and more rapid at the lower pH (p < 0.05). These studies demonstrated that lactate transport was increased with exercise. Key words: soleus, EDL, treadmill exercise

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