Ca2+-ATPase deficiency in a patient with an exertional muscle pain syndrome.
31P Magnetic resonance spectroscopy studies were carried out in vivo on skeletal muscle of a patient with verapamil-responsive, chronic, progressive post-exertional muscle pain. A sister suffered from a similar complaint. The results showed that the muscle: (1) decreased its high energy phosphate content more rapidly than normal during exercise, indicating either increased utilisation or decreased production of ATP; (2) acidified more rapidly than normal during exercise suggesting an increased glycolytic rate; (3) continued in some studies to acidify markedly during the first minute after exercise, indicating that glycolysis remained active into the recovery period; (4) had phosphocreatine and ADP recovery rates consistent with normal rates of oxidative phosphorylation. On the basis of these results, it was proposed that the patient suffers from a defect in Ca2+ handling in the muscle. Subsequently, direct measurement of Ca2+-ATPase activity in the sarcoplasmic reticulum fraction from a muscle biopsy sample showed that the activity of this enzyme was reduced by about 90%.
Taylor
D J
DJ
MRC Biochemical and Clinical Magnetic Resonance Unit, University of Oxford, UK.
Brosnan
M J
MJ
Arnold
D L
DL
Bore
P J
PJ
Styles
P
P
Walton
J
J
Radda
G K
GK
D000328:Adult; D000252:Calcium-Transporting ATPases / Q000172:deficiency*; D005080:Exercise Test; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009120:Muscle Cramp / Q000188:drug therapy / Q000201:enzymology*; D005082:Physical Exertion; D014700:Verapamil / Q000627:therapeutic use
D014700:Verapamil; D000252:Calcium-Transporting ATPases