Modulation of IkappaB kinase autophosphorylation and activity following brain ischemia.

AIM: To investigate the effects of different antagonists on the alteration of I?B kinase (IKK) activity in rat hippocampus following global brain ischemia. METHODS: Using 4-vessel occlusion (4-VO) as brain ischemia model, IKK protein expression was examined by immunoblotting and immunoprecipitation, and IKK activity was assayed by in vitro kinase assay. RESULTS: There was no alteration of IKK protein expression following ischemia or ischemia/reperfusion different time points, but IKK activity reached its peak level at ischemia 30 min. Pretreatment with N-methyl-D-aspartate (NMDA) receptor antagonist ketamine, non-NMDA receptor antagonist DNQX, or NF-kappaB inhibitor PDTC decreased the IKK activity following brain ischemia 30 min. The increase in substrate myelin basic protein (MBP) phosphorylation by IKK is associated with an increase in autophosphorylation of IKK, which can also be antagonized by ketamine, DNQX, and PDTC. CONCLUSION: NMDA receptor and non-NMDA receptor mediate the increase of IKK activity following global brain ischemia in rat hippocampus, which contributes to the alterations of expression and activity of downstream factor NF-kappaB.