[Increase of mitogen-activated protein kinase activity in rat brain after injection of argipressin (4-8)].
AIM
To study the changes of mitogen-activated protein kinase (MAPK) activity in rat brain stimulated by argipressin (4-8) (AVP (4-8)) (s.c.).


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).