Tanigawa T, Kotake Y, Reinke L A
National Biomedical Center for Spin Trapping and Free Radicals, Oklahoma Medical Research Foundation, Oklahoma City.
Free Radic Biol Med. 1993 Oct;15(4):425-33. doi: 10.1016/0891-5849(93)90042-s.
Oxygen radical formation by human neutrophils stimulated with a chemotactic peptide, formyl-methionyl-leucyl-phenylalanine (fMLP), was studied through the use of spin trapping and superoxide dismutase-inhibitable reduction of oxidized cytochrome c. Both methods provided comparable data on temperature-dependent kinetics of superoxide radical formation, but hydroxyl radicals were also detected in spin-trapping experiments. When superoxide generation was monitored at 37 degrees C, the respiratory burst lasted only a few minutes. If the neutrophils were stimulated at 37 degrees C, but superoxide measurements were done at room temperature, the respiratory burst was again transient. However, neutrophils persistently generated superoxide when both stimulation and subsequent measurements were performed at room temperature. In the presence of the actin polymerization inhibitor, cytochalasin B, superoxide generation was persistent, even when measurements were conducted at 37 degrees C. A possible explanation for these observations is that the fMLP receptor complexes quickly aggregate and are internalized at physiological temperature, but not at room temperature. Very little superoxide was formed if cells were kept at a temperature of 4 degrees C for 1 h prior to fMLP addition, which is consistent with decreased expression of the fMLP receptor at cold temperatures.
通过自旋捕集以及超氧化物歧化酶抑制的氧化型细胞色素c还原反应，研究了趋化肽甲酰甲硫氨酰亮氨酰苯丙氨酸（fMLP）刺激的人中性粒细胞产生氧自由基的情况。两种方法都提供了关于超氧自由基形成的温度依赖性动力学的可比数据，但在自旋捕集实验中也检测到了羟基自由基。当在37℃监测超氧化物生成时，呼吸爆发仅持续几分钟。如果在37℃刺激中性粒细胞，但在室温下进行超氧化物测量，呼吸爆发同样是短暂的。然而，当刺激和后续测量均在室温下进行时，中性粒细胞持续产生超氧化物。在肌动蛋白聚合抑制剂细胞松弛素B存在的情况下，即使在37℃进行测量，超氧化物生成也是持续的。对这些观察结果的一种可能解释是，fMLP受体复合物在生理温度下会迅速聚集并内化，但在室温下不会。如果在添加fMLP之前将细胞在4℃保持1小时，则几乎不形成超氧化物，这与低温下fMLP受体表达降低一致。
