Immunohistochemical localization of voltage-gated potassium channel Kv3.4 subunit was studied in the guinea-pig cochlea. Kv3.4-like immunoreactivity was present in the type I and suprastrial fibrocytes of the spiral ligament and the basal cells of the stria vascularis. Immunostaining was also found in the type II-IV fibrocytes of the spiral ligament and the connective tissue cells of the spiral limbus. In the organ of Corti, Kv3.4-like immunoreactivity was found in the sensory cells and the neighboring supporting cells. The root cells and interdental cells were positively immunostained. Immunoreactivity was also found in the endothelial cells of the blood vessels in the cochlear modiolus. These results suggest that Kv3.4 may participate in the potassium ion recycling mechanism in the cochlea
