Voltage‐dependent potassium currents of novel threadlike structure on the surface of internal organs in rats

Abstract

The electrophysiological properties of novel threadlike structure (NTS) on the surface of internal organs were investigated using whole cell patch clamp technique. NTS had well‐developed branches and were joined to a corpuscle (NTSC). Voltage clamp analysis revealed that the current‐voltage relationship (I–V) was highly non‐linear and can be divided into four types (Type I ~ IV) by slope conductance and their passive membrane properties in NTS cells. The outward current was inhibited, while residual currents were existed in outward and inward currents, by the voltage‐dependent potassium (Kv) channel blocker, tetraethylammonium (TEA), in a concentration‐dependent manner (IC50: 4.30 ± 1.71 and 4.43 ± 1.92 mM at +60 mV and −60 mV, respectively). These results indicated that the current was mainly carried by K+ ions. In addition, the resting membrane potential was depolarized by administration of 30 mM TEA. A systematic screening using RT‐PCR technique showed that genes of Kv1.2, Kv1.3, Kv2.1, Kv3.2, Kv3.3, Kv3.4, Kv4.1, Kv4.2 and Kv4.3 were expressed in NTSC. Taken together, our results indicated that Kv channel has an important role in regulating the membrane potential of NTSC cells.