Src family tyrosine kinase inhibitors suppress Nav1.1 expression in cultured rat spiral ganglion neurons.

Src family kinases regulate neuronal voltage-gated Na(+) channels, which generate action potentials. The mechanisms of action, however, remain poorly understood. The aim of the present study was to further elucidate the effects of Src family kinases on Nav1.1 mRNA and protein expression in spiral ganglion neurons. Immunofluorescence staining techniques detected Nav1.1 expression in the spiral ganglion neurons. Additionally, quantitative PCR and western blot techniques were used to analyze Nav1.1 mRNA and protein expression, respectively, in spiral ganglion neurons following exposure to Src family kinase inhibitors PP2 (1 and 10 μM) and SU6656 (0.1 and 1 μM) for different lengths of time (6 and 24 h). In the spiral ganglion neurons, Nav1.1 protein expression was detected in the somas and axons. The Src family kinase inhibitors PP2 and SU6665 significantly decreased Nav1.1 mRNA and protein expression (p < 0.05), respectively, in the spiral ganglion neurons, and changes in expression were not dependent on time or dose (p > 0.05).