Figure 5.
NaCN depolarizes resting membrane potential (Em), reduces action potential (AP) amplitude, and prolongs action potential duration (APD). These changes were rescued bymethylene blue (MB).AP parameters weremeasured in cultured human embryonic neurons by whole-cell patch clamp (see the materials and methods section). PBS (CTL) or NaCN (100 μM) was added at time zero, and AP wasmeasured at 10minutes. In another group of neurons,MB (20 μg/mL) was added 3 min after NaCN and action potential was measured at 10 minutes. Top: Representative AP tracings from neurons treated with PBS (CTL) (A), NaCN (B), and NaCN+MB (C). Bottom: Themeans ±SE of resting Em, APD at 100% repolarization (APD100), and AP amplitude from five CTL (D), seven NaCN (E), and six NaCN + MB (F) neurons (two human fetal brain preparations). *P ≤ 0.0007, CTL versus NaCN; and #P < 0.0015, NaCN versus NaHS + MB.