精氨加压素(4-8)刺激大鼠脑内促细胞分裂素活化的蛋白激酶活性增高

Increase of mitogen activated protein kinase activity in rat brain after injection of argipressin(4-8)

目的：研究精氨加压素（４－８）（ＡＶＰ（４－８））对大鼠脑内促细胞分裂素活化的蛋白激酶（ＭＡＰＫ）活性变化的影响．方法：大鼠皮下注射ＡＶＰ（４－８）后，通过柱分离后测定脑组织匀浆液中ＭＡＰＫ对其特异性底物髓脂质碱性蛋白（ＭＢＰ）的磷酸化活性．结果：ＡＶＰ（４－８）刺激的大鼠海马和大脑皮层中的４４ｋＤａＭＡＰＫ活性显著增高．这种活性增高被ＡＶＰ（４－８）的拮抗剂ＺＤＣ（Ｃ）ＰＲ降低８０％．ＭＡＰＫ蛋白量变化不受ＡＶＰ（４－８）刺激的影响．在海马切片实验中，也得到一致的结果．结论：ＡＶＰ（４－８）引起的４４ｋＤａＭＡＰＫ活性增高是一种由受体介导的细胞内短时期的酶激活过程，与蛋白质表达量的变化无关．ＭＡＰＫ参与了ＡＶＰ（４－８）诱导的皮层和海马内信号转导途径．

IM: To study the changes of mitogen activated protein kinase (MAPK) activity in rat brain stimulated by argipressin(4-8) (AVP(4-8)) (sc). METHODS: Wistar rat was treated with AVP(4-8). MAPK activity in rat brain was assayed by phosphorylation of its specific substrate myelin basic protein (MBP) after the cytosolic extracts fractionated by MONO Q anion exchange chromatography. RESULTS: The activity of 44 kDa MAPK in rat brain was significantly enhanced by AVP(4-8). The enhancement of MAPK activity in hippocampus was suppressed 80 % by ZDC(C)CPR , an antagonist of AVP(4-8). The level of 44 kDa MAPK protein had no detectable differences between the administration groups and control. In rat hippocampal slices, similar results were obtained. CONCLUSION: The increasement of 44 kDa MAPK activity stimulated by AVP(4-8) was mediated by its specific receptor, and was a short period process activated by protein phosphorylation, but not by protein expression. MAPK was involved in the signal transduction pathway induced by AVP(4-8).