Increased cytosolic free Mg2+ and Ca2+ in platelets of patients with vasospastic angina.
This study was designed to test the hypothesis that the cellular metabolism of Ca2+ and Mg2+, which is important in platelet function, is abnormal in the platelets of patients with vasospastic angina. Cytosolic free Mg2+ concentration ([Mg2+]i) and Ca2+ handling were determined in the platelets of 24 patients with vasospastic angina and 24 control subjects by use of mag-fura 2 and fura 2. Platelet aggregation was also examined. Basal [Mg2+]i and cytosolic free Ca2+ concentration ([Ca2+]i) in platelets were significantly higher in patients with vasospastic angina than in control subjects. The amplitude of the [Ca2+]i transient induced by thrombin (0.03-1.0 U/ml) was significantly increased in the presence, but not in the absence, of extracellular Ca2+ in patients with vasospastic angina, as compared with controls. Therefore, the influx of Ca2+ across the plasma membrane may be accelerated in vasospastic angina. Thrombin (0.1-1.0 U/ml)-induced maximum aggregation response was significantly greater in patients with vasospastic angina than in controls. Results suggest that increased [Mg2+]i and altered Ca2+ handling by platelets may be associated with coronary vasospasm.
Yoshimura
M
M
First Department of Internal Medicine, Hiroshima University School of Medicine, Japan.
Oshima
T
T
Hiraga
H
H
Nakano
Y
Y
Matsuura
H
H
Yamagata
T
T
Shiode
N
N
Kato
M
M
Kambe
M
M
Kajiyama
G
G
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000097:blood* / Q000150:complications; D001792:Blood Platelets / Q000648:ultrastructure*; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003329:Coronary Vasospasm / Q000097:blood* / Q000150:complications; D003600:Cytosol / Q000378:metabolism*; D005456:Fluorescent Dyes; D016257:Fura-2; D006801:Humans; D008274:Magnesium / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation; D013917:Thrombin / Q000494:pharmacology
D005456:Fluorescent Dyes; D000244:Adenosine Diphosphate; D013917:Thrombin; D008274:Magnesium; D002118:Calcium; D016257:Fura-2