Sodium cyanate-induced opening of calcium-activated potassium currents in hippocampal neuron-derived H19-7 cells

We investigated the chemical toxic agent sodium cyanate (NaOCN) on the large conductance calcium-activated potassium channels (BK_Ca) on hippocampal neuron-derived H19-7 cells. The whole-cell and cell-attach configuration of patch-clamp technique were applied to investigate the BK _Ca currents in H19-7 cells in the presence of NaOCN (0.3 mM). NaOCN activated BK_Ca channels on H19-7 cells. The single-channel conductance of BK_Ca channels was 138 ± 7 pS. The presence of NaOCN (0.3 mM) caused an obvious increase in open probability of BK_Ca channels. NaOCN did not exert effect on the slope of the activation curve and stimulated the activity of BK_Ca channels in a voltage-dependent fashion in H19-7 cells. The presence of paxilline or EGTA significantly reduced the BK_Ca amplitude, in comparison with the presence of NaOCN. These findings suggest that during NaOCN exposure, the activation of BK_Ca channels in neurons could be one of the ionic mechanisms underlying the decreased neuronal excitability and neurological disorders.