TOCP对DFP在鸡脊髓神经细胞膜特异结合的影响

Effect of tri-o-cresyl phosphate pretreatment on high-affinity bind of diisopropyfluorophosphate to membrane-bound proteins of chicken s pinal cord

关键词:  迟发性神经毒性；有机磷化合物；鸡；脊髓神经细胞膜  tri-o-cresyl phosphate (TOCP)；diisopropylfluorophosphate (DFP)

Key words:  delayed neurotoxicity  organophosphate  chicken  Tri-o-cresyl phosphate (TOCP)  diisopropylfluorophosphate (DFP)

摘要:

［目的］调查〔3H〕DFP 在各脊髓段神经细胞膜上的特异结合。［方法］鸡曝露于Tr i-o-cresyl phosphate (TOCP)后，隔6、24、48 h处死，取颈、胸、腰段脊髓，称重后制成 匀浆。经超速离心，获得膜蛋白。在脊髓膜蛋白中加入8 nM的〔3H〕DFP，或加入80 nM的 非标记DFP后又加入8 nM的〔3H〕DFP，然后培养1 h。用nitrocellulose filter进行快速 真空滤过，用Tris-HCl-NaCl液对滤纸冲洗，再加5 mL 的Aquasol-2后，计数〔3H〕DFP的 结合量。［结果］对照组鸡的颈、胸、腰椎段脊髓神经细胞膜上的〔3H〕DFP特异结合量 分别为832.0、857.0、864.0 fmol/mg，TOCP曝露组为273.5、243.5、271.5 fmol/mg。TOCP 曝露组各段脊髓神经细胞膜上的〔3H〕DFP特异结合量显著 低于对照组，而各段脊髓神经细胞膜之间〔3H〕DFP的特异结合量无显著性差异。随着TOC P曝露后的时间的推移，各段脊髓神经细胞膜上的〔3H〕DFP特异结合量逐渐增高，提示迟 发 性神经毒性有机磷化合物的特异结合膜蛋白是较均匀地分布在整个脊髓神经细胞膜上。在这 些脊髓神经细胞膜上的特异性结合部位，TOCP和DFP之间有竞争性抑制作用。［结论］脊髓 神经细胞膜上的特异性结合膜蛋白可能与有机磷化合物的迟发性神经毒性诱发有关。

Abstract:

［Objective］ To investigate high-affinity bind of t he delayed neurotoxic organophosphate to membrane-bound proteins from different sections of the chicken spinal cord. ［Methods］ The chickens were sacrificed 6, 24 and 48 hrs after Tri-o-cresyl phosphate (TOCP) treatment and spinal cords we re taken out. Membrane-bound proteins were prepared and the protein sites that l abeled with a low concentration of〔3H〕DFP were defined as the high-affinity binding sites. ［Results］ Amount of〔3H〕DFP binding to membrane-bound protei ns of nerve cells in the cervical, thoracic and lumbar vertebrae was 832.0，8 57.0，864.0 fmol/mg in controls，respectively, and 273.5，243.5，271.5 fmo l/mg in TOCP group. There was significant difference between gr oups and not between different sections of spinal cord in the same group. These results showed that TOCP metabolites interacted with the DFP binding sites and t hat membrane-bound proteins with DFP were relatively evenly distributed in chick en spinal cord membranes. ［Conclusions］ It indicates that the membrane-bound proteins may be associated with the organophosphate-induced delayed neurotoxicity (OPIDN).