NS13001 (N-(4-Chlorophenyl)-2-(3,5-dimethyl-1H-pyrazol-1-yl)-9-methyl-9H-purin-6-amine) is a potent, selective, orally active allosteric positive modulator of SK channels (small conductance calcium-activated potassium channels). The EC50s are 1.8 and 0.14 μM for SK2 and SK3, respectively. NS13001 holds promise as a potential therapeutic agent for treatment of spinocerebellar ataxia type 2 (SCA2) and possibly other cerebellar ataxias.