Bosin T R, Kasper G C
Pharmacology Section, Indiana University School of Medicine, Bloomington 47405.
J Biochem Toxicol. 1992 Fall;7(3):139-45. doi: 10.1002/jbt.2570070302.
The purpose of this study was to determine the effects of diamide, a reversible sulfhydryl oxidizing agent, on the transport of serotonin (5-HT) by mouse platelets. Diamide produced a concentration-dependent (10-200 microM) stimulation of 5-HT transport that was rapid and sustained over 0-10 minutes of incubation. When platelets were incubated with diamide (10-200 microM) in the presence of glucose, the content of reduced glutathione was significantly decreased only at a final concentration of 200 microM, while washed platelets incubated with diamide (10-200 microM), in the absence of glucose, had a significant concentration-dependent decrease in their content of reduced glutathione. Fluoxetine, an inhibitor of the platelet 5-HT transporter, blocked diamide-induced stimulation of 5-HT transport. The kinetics of 5-HT transport showed that diamide caused a marked increase in the maximal rate of transport (Vmax control = 28.4 +/- 1.4 vs. Vmax diamide = 60.9 +/- 4.1 pM/10(8) platelets/4 min) but did not significantly alter the Km values. Ouabain, an inhibitor of platelet Na(+)-K+ ATPase, blocked the stimulation by diamide in a concentration-dependent manner. Dithiothreitol, a disulfide reducing agent, was able to partially reverse the stimulation of platelet 5-HT transport caused by diamide. This study has shown that diamide can stimulate the active transport of 5-HT by mouse platelets and suggests a possible role for free sulfhydryl groups in the regulation of this process.
本研究的目的是确定可逆性巯基氧化剂二酰胺对小鼠血小板中5-羟色胺（5-HT）转运的影响。二酰胺对5-HT转运产生浓度依赖性（10 - 200 microM）刺激，这种刺激迅速且在孵育0 - 10分钟内持续存在。当血小板在葡萄糖存在下与二酰胺（10 - 200 microM）孵育时，仅在最终浓度为200 microM时还原型谷胱甘肽含量显著降低，而在无葡萄糖条件下与二酰胺（10 - 200 microM）孵育的洗涤血小板，其还原型谷胱甘肽含量呈显著的浓度依赖性降低。血小板5-HT转运体抑制剂氟西汀可阻断二酰胺诱导的5-HT转运刺激。5-HT转运动力学表明，二酰胺使转运的最大速率显著增加（对照组Vmax = 28.4 +/- 1.4，二酰胺组Vmax = 60.9 +/- 4.1 pM/10(8)个血小板/4分钟），但未显著改变Km值。血小板钠钾ATP酶抑制剂哇巴因以浓度依赖性方式阻断二酰胺的刺激作用。二硫苏糖醇，一种二硫化物还原剂，能够部分逆转二酰胺对血小板5-HT转运的刺激。本研究表明二酰胺可刺激小鼠血小板对5-HT的主动转运，并提示游离巯基在该过程调节中可能发挥作用。
