Immunohistochemical study on the distribution of six members of the Kv1 channel subunits in the rat cerebellum.

Voltage-gated K(+) (Kv) channels are critical for a wide variety of processes, and play an essential role in neurons. In the present study, we have demonstrated a unique pattern of expression of the six Kv1 channel subunits in the rat cerebellum, for the first time. The greatest concentration of Kv1.2 was found in the basket cell axon plexus and terminal regions around the Purkinje cells. Relatively weak immunoreactivity for Kv1.1 was also found in this area. The somatodendritic Purkinje cell areas were intensely stained with anti-Kv1.5 antibodies. In the cerebellar nuclei, the cell bodies of cerebellar output neurons showed strong Kv1.5 and Kv1.6 immunoreactivities in the nucleus medialis, interpositus and lateralis. Interestingly, Kv1.2 immunoreactivity was found in some neurons with their processes. Our immunohistochemical results may support the notion that the formation of heteromultimeric Kv channels possibly represents an important contribution to the generation of Kv channel diversity in the brain, especially in the cerebellum.