Voltage-dependent potassium channels in cultured mammalian Schwann cells.

Voltage-dependent ionic currents were recorded from cultured mammalian Schwann cells (rabbits, mice, rats and humans), by a whole-cell voltage-clamp technique to clarify the properties of voltage-dependent K+ currents in Schwann cells of various species. Voltage-dependent K+ channels were classified into 3 groups according to the degree of inactivation and sensitivity to blockade by tetraethylammonium (TEA): (1) little inactivation and TEA sensitivity (rabbit); (2) rapid inactivation and TEA resistance (rat and human); and (3) intermediate degree of both inactivation and sensitivity to TEA (mouse). In rabbit Schwann cells TEA blocked K+ channels predominantly from outside of the cells, while in the other species K+ channels were blocked by TEA inside the Schwann cells. The voltage-dependent K+ channels in different species had different electrophysiological and pharmacological properties, nevertheless the K+ channels in mammalian Schwann cells were similar to those observed in human or murine T-lymphocytes which are very sensitive to blockade by quinine. Although the culture conditions of human Schwann cells were different from those of other species, K+ channels in human Schwann cells were more similar to rat K+ channels than to those of rabbits or mice.