Figure 2.

Cell quantification after exposure to elevated K⁺. Cerebellar granule neurons from mutant (−/−), heterozygote (+/−), and normal (+/+) mice were cultured in 96-well plastic plates for 7 days in varying concentrations of KCl, as described. Results are expressed relative to MTT values obtained with cells from the same animal grown in 5 mM KCl. There was no significant difference of absolute MTT values between the 3 genotypes at 5 mM KCl (not shown). Normal and heterozygote cell survival increased at all concentrations of KCl, whereas mutant cell survival decreased markedly at 55 mM KCl. P values compare CGN from knockout mice with those from wild type. (Bars = SD; n = 3.)