AJP - Cell Physiology, Vol 248, Issue 3 337-C347, Copyright © 1985 by American Physiological Society

ARTICLES

Effects of acidosis on rat muscle metabolism and performance during heavy exercise

L. L. Spriet, C. G. Matsos, S. J. Peters, G. J. Heigenhauser and N. L. Jones

The metabolism and performance of a perfused rat hindquarter preparation was examined during heavy exercise in three conditions: control (C), metabolic acidosis (MA, decreased bicarbonate concentration), and respiratory acidosis (RA, increased CO2 tension). A one-pass system was used to perfuse the hindquarters for 30 min at rest and 20 min during tetanic stimulation via the sciatic nerve. The isometric tension generated by the gastrocnemius-plantaris-soleus muscle group was recorded, and biopsies were taken pre- and postperfusion. Initial isometric tensions were similar in all conditions, but the rate of tension decay was largest in acidosis; the 5-min tensions for C, MA, and RA were 1,835 +/- 63, 1,534 +/- 63, and 1,434 +/- 73 g, respectively. O2 uptake in C was greater than in MA and RA (23.4 +/- 1.3 vs. 17.0 +/- 1.4 and 16.5 +/- 2.3 mumol X min-1), paralleling the tension findings. Hindquarter lactate release was greatest in C, least in MA, and intermediate in RA. Acidosis resulted in less muscle glycogen utilization and lactate accumulation than during control. Muscle creatine phosphate utilization and ATP levels were unaffected by acidosis. Acidosis decreased the muscle's ability to generate isometric tension and depressed both aerobic and anaerobic metabolism. During stimulation in this model lactate left the muscle mainly as a function of the production rate, although a low plasma bicarbonate concentration at pH 7.15 depressed muscle lactate release.

This article has been cited by other articles:

				D. G. Allen, G. D. Lamb, and H. Westerblad Skeletal Muscle Fatigue: Cellular Mechanisms Physiol Rev, January 1, 2008; 88(1): 287 - 332. [Abstract] [Full Text] [PDF]

				M. Broch-Lips, K. Overgaard, H. A. Praetorius, and O. B. Nielsen Effects of extracellular HCO3 on fatigue, pHi, and K+ efflux in rat skeletal muscles J Appl Physiol, August 1, 2007; 103(2): 494 - 503. [Abstract] [Full Text] [PDF]

				G. D. Lamb, D. G. Stephenson, J. Bangsbo, and C. Juel Point:Counterpoint: Lactic acid accumulation is an advantage/disadvantage during muscle activity J Appl Physiol, April 1, 2006; 100(4): 1410 - 1412. [Full Text] [PDF]

				M. G. Hollidge-Horvat, M. L. Parolin, D. Wong, N. L. Jones, and G. J. F. Heigenhauser Effect of induced metabolic alkalosis on human skeletal muscle metabolism during exercise Am J Physiol Endocrinol Metab, February 1, 2000; 278(2): E316 - E329. [Abstract] [Full Text] [PDF]

				M. G. Hollidge-Horvat, M. L. Parolin, D. Wong, N. L. Jones, and G. J. F. Heigenhauser Effect of induced metabolic acidosis on human skeletal muscle metabolism during exercise Am J Physiol Endocrinol Metab, October 1, 1999; 277(4): E647 - E658. [Abstract] [Full Text] [PDF]

				V. L. Hood and R. L. Tannen Protection of Acid-Base Balance by pH Regulation of Acid Production N. Engl. J. Med., September 17, 1998; 339(12): 819 - 826. [Full Text] [PDF]

				J. D. Bruton, J. Lannergren, and H. Westerblad Effects of CO2-induced acidification on the fatigue resistance of single mouse muscle fibers at 28°C J Appl Physiol, August 1, 1998; 85(2): 478 - 483. [Abstract] [Full Text] [PDF]

				H. Pilegaard and S. Asp Effect of prior eccentric contractions on lactate/H+ transport in rat skeletal muscle Am J Physiol Endocrinol Metab, March 1, 1998; 274(3): E554 - E559. [Abstract] [Full Text] [PDF]