Kvl.l and Kvl.3 channels contribute to the delayed-rectifying K~+ conductance in rat choroid plexus epithelial cells

摘要

The choroid plexuses secrete, and maintain the composition of, the cerebrospinal fluid, K~+ channels play an important role in these processes. In this study the molecular identity and properties of the delayed-rectifying K~+ (Kv) conductance in rat choroid plexus epithelial cells were investigated. Whole cell K~+ currents were significantly reduced by 10 nM dendrotoxin-K and 1 nM margatoxin, which are specific inhibitors of Kvl.l and Kvl.3 channels, respectively. A combination of dendrotoxin-K and margatoxin caused a depolarization of the membrane potential in current-clamp experiments. Western blot analysis indicated the presence of Kvl.l and Kvl.3 proteins in the choroid plexus. Furthermore, the Kvl.3 and Kvl.l proteins appear to be expressed in the apical membrane of the epithelial cells in immunocytochemical studies.