The mutations in the GJB2 gene encoding for the connexin 26 (Cx26) protein are the most common source of nonsyndromic forms of deafness. Cx26 is a building block of gap junctions (GJ), establishing electrical intercellular connectivity between cells in distinct cochlear compartments. Cochlear circulation of ions such as potassium (K+) and metabolites such as IP3 is essential for normal hearing: animal models of the Cx26 deficiency in the organ of Corti (one of the compartments) seem to suggest the death of sensory cells (outer and inner hair cells, OHC and IHC, respectively) due to failed K+ homeostasis as the underlying problem. However, this mechanism may not be the only one. In search for alternative mechanisms we have used a large scale three-dimensional model of mechano-electrical transduction of sound in the cochlea (Mistrik et al., 2009). Indeed, a careful analysis revealed that reduced GJ conductivity in the organ of Corti would decrease the receptor potential across the OHC basolateral membrane. As the OHC electromotility is crucial for sound amplification granting the cochlear sensitivity and frequency selectivity we conclude that the reduction of the OHC somatic electromotility could represent an additional pathological mechanism in the Cx26 related forms of deafness.

Pavel Mistrík @VideoLectures.net