当前位置： SCI文献检索 > CANADIAN JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY期刊下所有文献 > Metabolic and sarcoplasmic reticulum Ca2+ cycling responses in human muscle 4 days following prolonged exercise.

Metabolic and sarcoplasmic reticulum Ca2+ cycling responses in human muscle 4 days following prolonged exercise.

Abstract：

: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.

journal_name

Can J Physiol Pharmacol

journal_title

Canadian journal of physiology and pharmacology

authors

Duhamel TA,Green HJ,Perco JG,Ouyang J

doi

10.1139/y05-049

subject

Has Abstract

pub_date

2005-07-01 00:00:00

pages

643-55

issue

eissn

0008-4212

issn

1205-7541

pii

y05-049

journal_volume

pub_type

临床试验,杂志文章

在线工具

Metabolic and sarcoplasmic reticulum Ca2+ cycling responses in human muscle 4 days following prolonged exercise.