Eliminating membrane depolarization caused by the Alzheimer peptide Abeta(1-42, aggr.)

A high-throughput screen found compounds that eliminate the dramatic membrane depolarization caused by the aggregated Alzheimer Abeta1-42 peptide, which activates mGluR1 receptors. The library was composed of known biologically active compounds; the cell-based assay measured the changes of membrane potential with a slow-acting voltage-sensitive dye. We found 10 potentially useful compounds, some of which reduce the Abeta-induced membrane depolarization up to 96%. Interestingly, the active compounds include specific tyrosine kinase inhibitors and inhibitors of certain chloride channels. We deduce that mGluR1 receptors, activated by Abeta1-42 or otherwise, can control the membrane potential via downstream activation of certain tyrosine kinases and certain ion channels. Dopaminergic and serotonergic agonists that emerged from the screen presumably compensate for the Abeta-induced membrane depolarization by themselves causing a hyperpolarization. The hit compounds, whose pharmacokinetics are known, show promise for the restoration of cognitive function in the treatment of early and mid-stage Alzheimer's disease.