A, effect of OA (100 nm) on peak Kv4.2 currents. a, time course of changes in normalized peak Kv4.2 currents measured at +40 mV under isosmotic, isosmotic + OA, and hyposmotic + OA conditions. b, I–V curves of Kv4.2 channels (n = 5) recorded using a protocol as described in Fig. 5 in isosmotic (Iso), isosmotic + OA (Iso + PDBu), and hyposmotic + OA (Hypo + OA) solutions. OA inhibited the currents under isosmotic conditions and prevented further activation by hyposmotic cell swelling. B, effects of CA (20 nm) on Kv4.2 channels. a, time course of changes in normalized peak Kv4.2 currents recorded at +40 mV under isosmotic, isosmotic + CA, and hyposmotic + CA conditions. b, mean I–V curves of Kv4.2 channels (n = 5) in isosmotic (Iso), isosmotic + CA (Iso + CA), and hyposmotic + CA (Hypo + BIM) solutions. CA inhibited the currents under isosmotic conditions and prevented further activation by hyposmotic cell swelling.