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Impaired muscle Ca2+ and K+ regulation contribute to poor exercise performance post-lung transplantation

McKenna, Michael J., Fraser, Steve F., Li, Jia L., Wang, Xiao N., Carey, Michael F., Side, Eleonora A., Morton, Judith, Snell, Gregory I., Kjeldsen, Keld and Williams, Trevor J. 2003, Impaired muscle Ca2+ and K+ regulation contribute to poor exercise performance post-lung transplantation, Journal of applied physiology, vol. 95, no. 4, pp. 1606-1616.

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Title Impaired muscle Ca2+ and K+ regulation contribute to poor exercise performance post-lung transplantation
Author(s) McKenna, Michael J.
Fraser, Steve F.ORCID iD for Fraser, Steve F. orcid.org/0000-0003-0202-9619
Li, Jia L.
Wang, Xiao N.
Carey, Michael F.
Side, Eleonora A.
Morton, Judith
Snell, Gregory I.
Kjeldsen, Keld
Williams, Trevor J.
Journal name Journal of applied physiology
Volume number 95
Issue number 4
Start page 1606
End page 1616
Total pages 11
Publisher American Physiological Society
Place of publication Bethesda, Md.
Publication date 2003-10
ISSN 8750-7587
1522-1601
Summary Lung transplant recipients (LTx) exhibit marked peripheral limitations to exercise. We investigated whether skeletal muscle Ca2+ and K+ regulation might be abnormal in eight LTx and eight healthy controls. Peak oxygen consumption and arterialized venous plasma [K+] (where brackets denote concentration) were measured during incremental exercise. Vastus lateralis muscle was biopsied at rest and analyzed for sarcoplasmic reticulum Ca2+ release, Ca2+ uptake, and Ca2+-ATPase activity rates; fiber composition; Na+-K+-ATPase (K+-stimulated 3-O-methylfluorescein phosphatase) activity and content ([3H]ouabain binding sites); as well as for [H+] and H+-buffering capacity. Peak oxygen consumption was 47% less in LTx (P < 0.05). LTx had lower Ca2+ release (34%), Ca2+ uptake (31%), and Ca2+-ATPase activity (25%) than controls (P < 0.05), despite their higher type II fiber proportion (LTx, 75.0 ± 5.8%; controls, 43.5 ± 2.1%). Muscle [H+] was elevated in LTx (P < 0.01), but buffering capacity was similar to controls. Muscle 3-O-methylfluorescein phosphatase activity was 31% higher in LTx (P < 0.05), but [3H]ouabain binding content did not differ significantly. However, during exercise, the rise in plasma [K+]-to-work ratio was 2.6-fold greater in LTx (P < 0.05), indicating impaired K+ regulation. Thus grossly subnormal muscle calcium regulation, with impaired potassium regulation, may contribute to poor muscular performance in LTx.
Language eng
Field of Research 110602 Exercise Physiology
110203 Respiratory Diseases
HERDC Research category C1.1 Refereed article in a scholarly journal
Persistent URL http://hdl.handle.net/10536/DRO/DU:30026443

Document type: Journal Article
Collection: School of Exercise and Nutrition Sciences
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