Current through the σ-pore was first detected in hKv1.3_V388C channels, where the V388C mutation in hKv.3wt opens a new pathway (σ-pore) behind the α-pore (Pruetting et al., JBC286:20031-2042). Typical for this mutant channel was inward current at potentials more negative than -100 mV when the central α-pore was closed. To see whether this phenomenon is restricted to Kv1.3 channels we mutated hKv1.2 at the homologue position (hKv1.2_V370C). By overexpression in COS7 cells hK1.2_V370C showed typical σ-current and currents through the hK1.2_V370C α-pore showed similar changes of current amplitude with repetitive pulses like in hK1.2 wild type channels. Electrophysiological properties of the σ-pore in hKv1.3_V388C and hK1.2_V370C were similar. The σ-pore of hK1.2_V370C channels was most permeable to Na+ and Li+ whereas Cl- and protons did not influence current through the σ-pore. The α-pore blockers such as TEA+ and peptide toxins (CTX, MTX) could not reduce current through the σ-pore.