Immunohistochemical study on the distribution of the voltage-gated potassium channels in the gerbil hippocampus.

The differential expression of specialized voltage-gated potassium (Kv) channel subtypes probably reflects the wide range of functions in the nervous system. In the present study, we investigated the distribution of six Kv1 channel subtypes in the gerbil hippocampus by immunohistochemistry. Immunoreactivities for Kv1.1, Kv1.2, Kv1.4 and Kv1.6 were observed in the pyramidal cells of the CA1-CA3 areas. In addition, many medium- to large-sized interneurons located within stratum pyramidals, stratum oriens, and stratum radiatum of CA1-CA3 were strongly immunoreactive for Kv1.4. Although there was some overlap, our results were quite different from the previous studies described in the rat and mouse hippocampus, in that we observed intense staining mainly in the cell bodies of the pyramidal cells and granule cells. As a whole, the present study has clearly shown Kv1 channel distributions in the gerbil hippocampus, which were variant between species and therefore more or less functionally significant. This study may provide useful data for the future investigations on the pathological conditions such as ischemia and epilepsy.