IONIC CHANNELS IN NONEXCITABLE CELLS

Several distinct types of voltage-gated and second-messenger-operated K+, Ca2+, Na+ and Cl- channels exist in electrically non excitable cel ls such as those of the hematopoietic lineage. In these cells ion chan nels mediate cellular functions involving intracellular biochemical re sponses, rather than rapid electrical signaling. The presence of the c hannels is required for several basic functions, such as activation, s ecretion of lymphokines, mitogenesis, the regulation of cell volume an d the mechanisms of resistance to chemotherapeutic agents. Here IN we review the patch-clamp method for studying many characteristics of the se ionic channels, particularly in blood cells.