RESUMO
BACKGROUND AND OBJECTIVES: Regular aerobic exercise plays a role in the prevention of cardiovascular diseases, but the risk of primary cardiac arrest transiently increases during vigorous exercise, particularly in sedentary men. There has been a controversy regarding the effect of exercise on platelet functional behavior, which is related to the pathogenesis of coronary ischemia. We evaluated the cytoplasmic free calcium concentration of platelets in healthy men after treadmill exercise. MATERIALS AND METHOD: Five physically active (group I: age, 24.2+/-2.3 years) and five sedentary men (group II: age, 22.4+/-1.4 years) were included in this study. Platelet calcium was measured with fluorescent dye, quin2 before and after treadmill exercise. RESULTS: Platelet calcium levels were increased from 86.8+/-11.8 nM to 128.8+/-15.0 nM in group I (p<0.05) and from 102.6+/-14.4 nM to 162.4+/-26.5 nM in group II (p<0.05) immediately after exercise. Thereafter, platelet calcium levels were decreased in group I, but continuously increased in group II. At fifteen minutes after exercise, platelet calcium concentrations were significantly higher than baseline values in group II (205.8+/-53.9 nM vs 102.6+/-14.4 nM: p<0.05), but not in group I (115.2+/-15.7 nM vs 86.8+/-11.8 nM). CONCLUSION: Cytoplasmic free calcium concentration in platelets were continuosly increased after treadmill exercise in sedentary men but not in physically active men.
Assuntos
Humanos , Masculino , Plaquetas , Cálcio , Doenças Cardiovasculares , Citoplasma , Exercício Físico , Parada Cardíaca , IsquemiaRESUMO
BACKGROUND AND OBJECTIVES: Regular aerobic exercise plays a role in the prevention of cardiovascular diseases, but the risk of primary cardiac arrest transiently increases during vigorous exercise, particularly in sedentary men. There has been a controversy regarding the effect of exercise on platelet functional behavior, which is related to the pathogenesis of coronary ischemia. We evaluated the cytoplasmic free calcium concentration of platelets in healthy men after treadmill exercise. MATERIALS AND METHOD: Five physically active (group I: age, 24.2+/-2.3 years) and five sedentary men (group II: age, 22.4+/-1.4 years) were included in this study. Platelet calcium was measured with fluorescent dye, quin2 before and after treadmill exercise. RESULTS: Platelet calcium levels were increased from 86.8+/-11.8 nM to 128.8+/-15.0 nM in group I (p<0.05) and from 102.6+/-14.4 nM to 162.4+/-26.5 nM in group II (p<0.05) immediately after exercise. Thereafter, platelet calcium levels were decreased in group I, but continuously increased in group II. At fifteen minutes after exercise, platelet calcium concentrations were significantly higher than baseline values in group II (205.8+/-53.9 nM vs 102.6+/-14.4 nM: p<0.05), but not in group I (115.2+/-15.7 nM vs 86.8+/-11.8 nM). CONCLUSION: Cytoplasmic free calcium concentration in platelets were continuosly increased after treadmill exercise in sedentary men but not in physically active men.
Assuntos
Humanos , Masculino , Plaquetas , Cálcio , Doenças Cardiovasculares , Citoplasma , Exercício Físico , Parada Cardíaca , IsquemiaRESUMO
AIM Aim to study the effect of PLC on human platelet cytoplasmic free calcium concentration, and then to explore the mechanism of PLC anti aggregation to platelet. METHODS Washed platelet of human was marked with fluorescence indicator Furu 2/AM, and then was treated with PSS, ASA and different dose of PLC respectively. Cytoplasmic free [Ca 2+ ] i of differently treated platelet at static state and activated sate induced by ADP was determined by double beam fluorescence spectrophotometric method. RESULTS Healthy human platelet was treated with PSS, ASA 334 ?mol?L -1 , 2 5, 3 75, 5, 10 and 20U PLC?ml -1 . Cytoplasmic [Ca 2+ ] i determined at static state was 152 55?15 07, 131 63?15 58, 140 27?12 03, 139 48?1 73, 121 11?9 58, 116 62?15 96 and 107 20?17 07 respectively. [Ca 2+ ] i determined at activated sate induced by ADP was 902 62?94 74, 687 99?62 86, 810 99?72 37, 701 73?21 37, 429 67?71 59, 342 82?44 86 and 263 27?25 46 respectively. Compared with PSS, inhibition rates ( % ) of ASA 334 ?mol?L -1 , 2 5, 3 75, 5,10, 20 U PLC?ml -1 to the increment of activated platelet cytoplasmic [Ca 2+ ] i were 25 83, 10 58, 25 04, 58 86, 69 84, 79 19 respectively. At the same condition, inhibition rate ( % ) of 10 U PLC?ml -1 to the increment of five hypertensive activated platelet cytoplasmic [Ca 2+ ] i were 74 25, 73 48, 61 32, 82 87,70 60 respectively. CONCLUSION PLC has significant effects on static cytoplasmic[Ca 2+ ] i of healthy and hypertensive human platelet ( P