Altered sarcoplasmic reticulum function in rat diaphragm after high‐intensity exercise

Matsunaga, Satoshi; Inashima, Shuichiro; Tsuchimochi, Hirotsugu; Yamada, Takashi; Hazama, Toshio; Wada, Masanobu

doi:10.1046/j.1365-201x.2002.01029.x

Cited by 9 publications

(7 citation statements)

References 25 publications

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“…It is possible, given the apparent increased SR membrane permeability, that the decrease in Ca 2ϩ uptake that we observed in SOL and RG with the contractile activity in this study could have been even more pronounced if a Ca 2ϩ leak through the membrane was present. Previous studies using different exercise protocols have not reported any changes in the ionophore ratio in SOL (54), red vastus/RG (5), or diaphragm (34).…”

Section: Discussionmentioning

confidence: 96%

Differential effects of repetitive activity on sarcoplasmic reticulum responses in rat muscles of different oxidative potential

Holloway¹,

Green²,

Tupling³

2006

American Journal of Physiology-Regulatory, Integrative and Comp

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We investigated the hypothesis that muscles of different oxidative potential would display differences in sarcoplasmic reticulum (SR) Ca2+ handling responses to repetitive contractile activity and recovery. Repetitive activity was induced in two muscles of high oxidative potential, namely, soleus (SOL) and red gastrocnemius (RG), and in white gastrocnemius (WG), a muscle of low oxidative potential, by stimulation in adult male rats. Measurements of SR properties, performed in crude homogenates, were made on control and stimulated muscles at the start of recovery (R0) and at 25 min of recovery (R25). Maximal Ca2+-ATPase activity (Vmax, micromol x g protein(-1) x min(-1)) at R0 was lower in stimulated SOL (105 +/- 9 vs. 135 +/- 7) and RG (269 +/- 22 vs. 317 +/- 26) and higher (P < 0.05) in WG (795 +/- 32 vs. 708 +/- 34). At R25, Vmax remained lower (P < 0.05) in SOL and RG but recovered in WG. Ca2+ uptake, measured at 2,000 nM, was depressed (P < 0.05) in SOL and RG by 34 and 13%, respectively, in stimulated muscles at R0 and remained depressed (P < 0.05) at R25. In contrast, Ca2+ uptake was elevated (P < 0.05) in stimulated WG at R0 by 9% and remained elevated (P < 0.05) at R25. Ca2+ release, unaltered in SOL and RG at both R0 and R25, was increased (P < 0.05) in stimulated WG at both R0 and R25. We conclude that SR Ca2+-handling responses to repetitive contractile activity and recovery are related to the oxidative potential of muscle.

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Section: Discussionmentioning

confidence: 96%

Differential effects of repetitive activity on sarcoplasmic reticulum responses in rat muscles of different oxidative potential

Holloway¹,

Green²,

Tupling³

2006

American Journal of Physiology-Regulatory, Integrative and Comp

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“…The different musclespecific responses are related to the oxidative potential of the muscle (13) and may reflect differences in second messenger regulation of SERCAs and/or redox homeostasis. Similarly, in response to different types of exercise, SR Ca 2ϩ uptake measured in rat diaphragm homogenates is either increased (43) or decreased (23), which may reflect differences in ROS production and/or second messenger activation, depending on the exercise protocol employed.…”

Section: Discussionmentioning

confidence: 99%

Effects of buthionine sulfoximine treatment on diaphragm contractility and SR Ca²⁺pump function in rats

Tupling¹,

Vigna²,

Ford³

et al. 2007

Journal of Applied Physiology

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The purpose of this study was to examine the effects of glutathione (GSH) depletion and cellular oxidation on rat diaphragm contractility and sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) function in vitro under basal conditions and following fatiguing stimulation. Buthionine sulfoximine (BSO) treatment (n = 10) for 10 days (20 mM in drinking water) reduced (P < 0.05) diaphragm GSH content (nmol/mg protein) and the ratio of GSH to glutathione disulfide (GSH/GSSG) by 91% and 71%, respectively, compared with controls (CTL) (n = 10). Western blotting showed that Hsp70 expression in diaphragm was not increased (P > 0.05) with BSO treatment. As hypothesized, basal peak twitch force (g/mm(2)) was increased (P < 0.05), and fatigability in response to repetitive stimulation (350-ms trains at 100 Hz once every 1 s for 5 min) was also increased (P < 0.05) in BSO compared with CTL. Both Ca(2+) uptake and maximal SERCA activity (mumol.g protein(-1).min(-1)) measured in diaphragm homogenates that were prepared at rest were increased (P < 0.05) with BSO treatment, an effect that could be partly explained by a twofold increase (P < 0.05) in SERCA2a expression with BSO. In response to the 5-min stimulation protocol, both Ca(2+) uptake and maximal SERCA activity were increased (P < 0.05) in CTL but not (P > 0.05) in BSO diaphragm. We conclude that 1) cellular redox state is more optimal for contractile function and fatigability is increased in rat diaphragm following BSO treatment, 2) SERCA2a expression is modulated by redox signaling, and 3) regulation of SERCA function in working diaphragm is altered following BSO treatment.

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“…SR Ca 2+ uptake rate was measured by using the fluorescent dye indo-1 as previously described in detail [23,25]. The assay mixture (pH 7.0) consisted of (in mM) 100 KCl, 20 HEPES, 6.8 K-oxalate, 10 Na-azide, 1 M indo-1, 0.5 MgCl 2 and 2 M free Ca 2+ .…”

Section: Ca2+ Uptake Measurementsmentioning

confidence: 99%

Oxidation of sarcoplasmic reticulum Ca2+-ATPase induced by high-intensity exercise

Matsunaga¹,

Inashima

Yamada

et al. 2003

Pflugers Arch - Eur J Physiol

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Ca(2+)-ATPase and Ca(2+)-pumping activities by the sarcoplasmic reticulum (SR) and the amounts of sulphydryl and carbonyl groups contained in the SR protein were examined in the superficial portion of the gastrocnemius and vastus lateralis muscles of the rat after high-intensity treadmill runs to exhaustion (average time to exhaustion: 363 s). Exercise at the estimated maximal O(2) uptake rate led to 16% and 34% reductions in SR Ca(2+)-ATPase activity ( P<0.01) and Ca(2+) uptake rate ( P<0.01), respectively. The carbonyl group content in SR Ca(2+)-ATPase, assessed by immunoblotting analysis, was increased by 127% after exercise ( P<0.05), while the sulphydryl group content in the purified SR fraction was unchanged. Consistent with the unchanged sulphydryl group content, treatment of homogenates with dithiothreitol, the disulphide reducing reagent, failed to restore the decreased catalytic activity of SR Ca(2+)-ATPase in exercised muscles. These findings show clearly that high-intensity, exhaustive exercise causes oxidation of SR Ca(2+)-ATPase protein and suggest that oxidation of amino acids, other than cysteine, in the SR Ca(2+)-ATPase may be responsible, at least in part, for exercise-induced inactivation of this enzyme.

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Altered sarcoplasmic reticulum function in rat diaphragm after high‐intensity exercise

Cited by 9 publications

References 25 publications

Differential effects of repetitive activity on sarcoplasmic reticulum responses in rat muscles of different oxidative potential

Differential effects of repetitive activity on sarcoplasmic reticulum responses in rat muscles of different oxidative potential

Effects of buthionine sulfoximine treatment on diaphragm contractility and SR Ca²⁺pump function in rats

Oxidation of sarcoplasmic reticulum Ca2+-ATPase induced by high-intensity exercise

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Altered sarcoplasmic reticulum function in rat diaphragm after high‐intensity exercise

Cited by 9 publications

References 25 publications

Differential effects of repetitive activity on sarcoplasmic reticulum responses in rat muscles of different oxidative potential

Differential effects of repetitive activity on sarcoplasmic reticulum responses in rat muscles of different oxidative potential

Effects of buthionine sulfoximine treatment on diaphragm contractility and SR Ca2+pump function in rats

Oxidation of sarcoplasmic reticulum Ca2+-ATPase induced by high-intensity exercise

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Product

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Effects of buthionine sulfoximine treatment on diaphragm contractility and SR Ca²⁺pump function in rats