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).