Effects of KN-62, a specific inhibitor of calcium/calmodulin-dependent protein kinase II, on long-term potentiation in the rat hippocampus.

Effects of KN-62 (1-[NO-bis-1,5-isoquinolinesulfonyl]-N-methyl-L-tyrosyl- 4-phenylpiperazine), a specific inhibitor of calcium/calmodulin-dependent protein kinase II, were examined using rat hippocampus slices in vitro. The inhibitor, when applied in bathing solutions prior to and present during the tetanic stimulations, blocked the generation of long-term potentiation (LTP) in CA1 regions without affecting basal synaptic transmission itself, suggesting an important role of this kinase in the molecular mechanism of CA1 LTP. In contrast, mossy fiber LTP in CA3 regions was not affected significantly by the inhibitor.