Expression of Ca(2+)-activated K(+) channel subunits and splice variants in the rat cochlea.

The recently manifested important role of the Ca(2+)-activated K(+) channels, especially of the Slo gene-coded channels, for the cochlea function of the chicken raised the question of homolog expression in mammalian inner ear tissue. Molecular biological methods were used to demonstrate the expression of Ca(2+)-activated K(+) channel subunits and splice variants of the Slo gene in the rat organ of Corti. RT-PCR experiments for the detection of rat Slo alpha subunit mRNA revealed the presence of several already known splice variants including variants which appeared to be typical for the organ of Corti (+58 aa) and for the brain (+61 aa). To detect the accessory beta subunit we used Southern blot hybridization. Our data support the hypothesis that Ca(2+)-activated K(+) channel subunits (i.e. Slo variants) are also involved in the hearing of mammals in the organ of Corti.