PMID- 16091790
OWN - NLM
STAT- MEDLINE
DCOM- 20060208
LR  - 20191210
IS  - 0008-4212 (Print)
IS  - 0008-4212 (Linking)
VI  - 83
IP  - 7
DP  - 2005 Jul
TI  - Metabolic and sarcoplasmic reticulum Ca2+ cycling responses in human muscle 4 
      days following prolonged exercise.
PG  - 643-55
AB  - This study investigated the effects of prolonged exercise on muscle sarcoplasmic 
      reticulum (SR) Ca2+ cycling properties and the metabolic responses with and 
      without a session of exercise designed to reduce muscle glycogen reserves while 
      on a normal carbohydrate (CHO) diet. Eight untrained males (VO(2peak) = 3.81 +/- 
      0.12 L/min, mean +/- SE) performed a standardized cycle-to-fatigue at 55% 
      VO(2peak) while on a normal CHO diet (Norm CHO) and 4 days following prolonged 
      exercise while on a normal CHO diet (Ex+Norm CHO). Compared to rest, exercise in 
      Norm CHO to fatigue resulted in significant reductions (p < 0.05) in Ca2+ uptake 
      (3.17 +/- 0.21 vs. 2.47 +/- 0.12 micromol.(g protein)-1.min-1), maximal Ca2+ 
      ATPase activity (Vmax, 152 +/- 12 vs. 119 +/- 9 micromol.(g protein)-1.min-1) and 
      both phase 1 (15.1 +/- 0.98 vs. 13.1 +/- 0.28 micromol.(g protein)-1.min-1) and 
      phase 2 (6.56 +/- 0.33 vs. 4.91 +/- 0.28 micromol.(g protein)-1.min-1) Ca2+ 
      release in vastus lateralis muscle. No differences were observed between Norm CHO 
      and Ex-Norm CHO in the response of these properties to exercise. Compared with 
      Norm CHO, Ex+Norm CHO resulted in higher (p < 0.05) resting Ca2+ uptake (3.17 +/- 
      0.21 vs. 3.49 +/- 0.24 micromol.(g protein).min-1 and higher ionophore ratio, 
      defined as the ratio of Vmax measured with and without the Ca2+-ionophore A23187, 
      (2.3 +/- 0.3 vs. 4.4 +/- 0.3 micromol.(g protein).min-1) at fatigue. No 
      differences were observed between conditions in the concentration of muscle 
      glycogen, the high-energy phosphates (ATP and PCr), or metabolites (Pi, Cr, and 
      lactate). Ex+Norm CHO also failed to modify the exercise-induced changes in CHO 
      and fat oxidation. We conclude that prolonged exercise to fatigue performed 4 
      days following glycogen-depleting exercise while on a normal CHO diet elevates 
      resting Ca2+ uptake and prevents increases in SR membrane permeability to Ca2+ as 
      measured by the ionophore ratio.
FAU - Duhamel, T A
AU  - Duhamel TA
AD  - Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, 
      Canada.
FAU - Green, H J
AU  - Green HJ
FAU - Perco, J G
AU  - Perco JG
FAU - Ouyang, J
AU  - Ouyang J
LA  - eng
PT  - Clinical Trial
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Canada
TA  - Can J Physiol Pharmacol
JT  - Canadian journal of physiology and pharmacology
JID - 0372712
RN  - 0 (Blood Glucose)
RN  - 0 (Dietary Carbohydrates)
RN  - 9005-79-2 (Glycogen)
RN  - EC 7.2.2.10 (Calcium-Transporting ATPases)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Adult
MH  - Anaerobic Threshold/physiology
MH  - Blood Glucose/metabolism
MH  - Calcium/*metabolism
MH  - Calcium-Transporting ATPases/metabolism
MH  - Diet
MH  - Dietary Carbohydrates/pharmacology
MH  - Exercise/*physiology
MH  - Glycogen/metabolism
MH  - Humans
MH  - Kinetics
MH  - Male
MH  - Muscle Fatigue/physiology
MH  - Muscle, Skeletal/*metabolism
MH  - Oxidation-Reduction
MH  - Oxygen Consumption/physiology
MH  - Pulmonary Gas Exchange/physiology
MH  - Sarcoplasmic Reticulum/*metabolism
EDAT- 2005/08/11 09:00
MHDA- 2006/02/09 09:00
CRDT- 2005/08/11 09:00
PHST- 2005/08/11 09:00 [pubmed]
PHST- 2006/02/09 09:00 [medline]
PHST- 2005/08/11 09:00 [entrez]
AID - y05-049 [pii]
AID - 10.1139/y05-049 [doi]
PST - ppublish
SO  - Can J Physiol Pharmacol. 2005 Jul;83(7):643-55. doi: 10.1139/y05-049.