The newly identified K+ channel blocker talatisamine attenuates beta-amyloid oligomers induced neurotoxicity in cultured cortical neurons.

Loss of cytosolic K(+) through up-regulated delayed rectifier K(+) channels play an important role in beta-amyloid (Aβ) induced neurotoxicity. Potent K(+) channel blocker, particular specific for I(K) channels has been suggested as an attractive candidate for the treatment of Alzheimer's disease (AD). Talatisamine is a novel I(K) channel blocker discovered by virtual screening and electrophysiological characterization. In the present study, we examined the neuroprotective effect of talatisamine against Aβ oligomers induced cytotoxicity in primarily cultured cortical neurons. The neurotoxicity related to K(+) loss caused by Aβ40 oligomers included enhanced I(K) density, increased cell membrane permeability, reduced cell viability, and impaired mitochondrial transmembrane potential. Decreased Bcl-2 and increased Bax level, activation of Caspase-3 and Caspase-9 were also observed after Aβ40 oligomers incubation. Talatisamine (120 μM) and TEA (5mM) inhibited the enhanced I(K) caused by Aβ40 oligomers, attenuated cytotoxicity of Aβ oligomers by restoring cell viability and suppressing K(+) loss related apoptotic response. Our results suggested that talatisamine may become a leading compound as I(K) channel blocker for neuroprotection.