Potassium channel gene expression in the rat cochlear nucleus.

Potassium channels play a critical role in defining the electrophysiological properties accounting for the unique response patterns of auditory neurons. Serial analysis of gene expression (SAGE), microarrays, RT-PCR, and real-time RT-PCR were used to generate a broad profile of potassium channel expression in the rat cochlear nucleus. This study identified mRNAs for 51 different potassium channel subunits or channel interacting proteins. The relative expression levels of 27 of these transcripts among the AVCN, PVCN, and DCN were determined by real-time RT-PCR. Four potassium channel transcripts showed substantial levels of differential expression. Kcnc2 was expressed more than 15-fold higher in the DCN as compared to AVCN and PVCN. In contrast, Kcnj13 had an approximate 10-fold higher expression in AVCN and PVCN than in DCN. Two subunits that modify the activity of other channels were inversely expressed between ventral and dorsal divisions. Kcns1 was over 15-fold higher in DCN than AVCN or PVCN, while Kcns3 was about 25-fold higher in AVCN than in DCN. The expression patterns of potassium channels in the subdivisions of the cochlear nucleus provide a basis for understanding the electrophysiological mechanisms which sub-serve central auditory processing and provide targets for further investigations into neural plastic changes that occur with hearing loss.