Probably important in the regulation of neuronal excitability. May underlie a potassium current involved in regulating the excitability of sensory cells of the cochlea. KCNQ4 channels are blocked by linopirdin, XE991 and bepridil, whereas clofilium is without significant effect. Muscarinic agonist oxotremorine-M strongly suppress KCNQ4 current in CHO cells in which cloned KCNQ4 channels were coexpressed with M1 muscarinic receptors. Mutagenesis experiments were carried out by expressing in Xenopus oocytes KCNQ4 mutants either individually (homomultimers) or in combination with wild-type KCNQ4 (mut/wt homomultimers) in a ratio of 1:1, to mimic the situation in a heterozygous DFNA2 patient.