Human muscle performance and PCr hydrolysis with varied inspired oxygen fractions:: a 31P-MRS study

被引:230
作者
Hogan, MC [1 ]
Richardson, RS [1 ]
Haseler, LJ [1 ]
机构
[1] Univ Calif San Diego, Dept Med, La Jolla, CA 92093 USA
关键词
skeletal muscle; fatigue; oxygen uptake; muscle bioenergetics; exercise; adenosine 5 '-triphosphate; adenosine 5 '-diphosphate; pH; inorganic phosphate; glycolysis; mitochondrial respiration; fraction of inspired oxygen; phosphocreatine; magnetic resonance spectroscopy;
D O I
10.1152/jappl.1999.86.4.1367
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
The purpose of this study was to use P-31-magnetic resonance spectroscopy to examine the relationships among muscle PCr hydrolysis, intracellular H+ concentration accumulation, and muscle performance during incremental exercise during the inspiration of gas mixtures containing different fractions of inspired O-2 (FIO2) We hypothesized that lower FIO2 would result in a greater disruption of intracellular homeostasis at submaximal workloads and thereby initiate an earlier onset of fatigue. Six subjects performed plantar flexion exercise on three separate occasions with the only variable altered for each exercise bout being the FIO2 (either 0.1, 0.21, or 1.00 O-2 in balance N-2). Work rate was increased (1-W increments starting at 0 W) every 2 min until. exhaustion. Time to exhaustion (and thereby workload achieved) was significantly (P < 0.05) greater as FIO2 was increased. Muscle phosphocreatine (PCr) concentration, P-i concentration, and pH at exhaustion were not significantly different among the three FIO2 conditions. However, muscle PCr concentration and pH were significantly reduced at identical submaximal workloads (and thereby equivalent rates of respiration) above 4-5 W during the lowest FIO2 condition compared with the other two FIO2 conditions. These results demonstrate that exhaustion during all Fret occurred when a particular intracellular environment was acheived and suggest that during the lowest FIO2 condition, the greater PCr hydrolysis and intracellular acidosis at submaximal workloads may have contributed to the significantly earlier time to exhaustion.
引用
收藏
页码:1367 / 1373
页数:7
相关论文
共 41 条
[1]   OXYGEN-UPTAKE, ACID-BASE STATUS, AND PERFORMANCE WITH VARIED INSPIRED OXYGEN FRACTIONS [J].
ADAMS, RP ;
WELCH, HG .
JOURNAL OF APPLIED PHYSIOLOGY, 1980, 49 (05) :863-868
[2]   BLOOD LACTATE AND OXYGEN DEBT AFTER EXHAUSTIVE WORK AT DIFFERENT OXYGEN TENSIONS [J].
ASMUSSEN, E ;
VONDOBELN, W ;
NIELSEN, M .
ACTA PHYSIOLOGICA SCANDINAVICA, 1948, 15 (01) :57-62
[3]   REGULATION OF OXIDATIVE-PHOSPHORYLATION IN THE MAMMALIAN-CELL [J].
BALABAN, RS .
AMERICAN JOURNAL OF PHYSIOLOGY, 1990, 258 (03) :C377-C389
[4]   CHANGES IN POTENTIAL CONTROLLERS OF HUMAN SKELETAL-MUSCLE RESPIRATION DURING INCREMENTAL CALF EXERCISE [J].
BARSTOW, TJ ;
BUCHTHAL, SD ;
ZANCONATO, S ;
COOPER, DM .
JOURNAL OF APPLIED PHYSIOLOGY, 1994, 77 (05) :2169-2176
[5]  
CHANCE B, 1955, J BIOL CHEM, V217, P383
[6]   ANALYSIS OF METABOLIC CONTROL - NEW INSIGHTS USING SCALED CREATINE-KINASE MODEL [J].
CONNETT, RJ .
AMERICAN JOURNAL OF PHYSIOLOGY, 1988, 254 (06) :R949-R959
[7]   ENERGY-SOURCES IN FULLY AEROBIC REST-WORK TRANSITIONS - A NEW ROLE FOR GLYCOLYSIS [J].
CONNETT, RJ ;
GAYESKI, TEJ ;
HONIG, CR .
AMERICAN JOURNAL OF PHYSIOLOGY, 1985, 248 (06) :H922-H929
[8]   ENERGY-METABOLISM IN CONTRACTING RAT SKELETAL-MUSCLE - ADAPTATION TO EXERCISE TRAINING [J].
CONSTABLE, SH ;
FAVIER, RJ ;
MCLANE, JA ;
FELL, RD ;
CHEN, M ;
HOLLOSZY, JO .
AMERICAN JOURNAL OF PHYSIOLOGY, 1987, 253 (02) :C316-C322
[9]  
DUDLEY GA, 1987, J BIOL CHEM, V262, P9104
[10]   CELLULAR MECHANISMS OF MUSCLE FATIGUE [J].
FITTS, RH .
PHYSIOLOGICAL REVIEWS, 1994, 74 (01) :49-94