EN
Voltage-gated potassium channels (Kv) are predominating and most widely studied ion channels in T lymphocytes (TL). Patch-clamp studies provide evidence that three different types of Kv channels, termed n, n' and l, are present in human in mouse TL. This review focuses on: 1) studies on biophysical properties of the three channel types, 2) role of Kv channels in TL cell function. Available data demonstrate that the activity of Kv channels in TL is required for: i. setting the TL resting membrane potential, ii. cell mitogenesis, iii. volume regulation. Blockade of Kv channels effectively blocks both mitogenesis and volume regulation of T cells, 3) changes of Kv channel expression in diseases. Results of patch-clamp studies provide evidence that expression of TL Kv channels is significantly altered in autoimmune diseases and in chronic renal failure. Autoimmune diseases are linked to an abnormally high expression of the l type Kv channels, which arises in parallel with the onset of autoimmunity, in mouse double-negative (DN-CD4-CD8-) TL. In chronic renal failure, a significant increase in the whole-cell potassium conductance (gKv), probably also due to altered channel expression, appears in human TL. The rise in the gKv value parallels the onset of the disease. Moreover, long-term therapy of uremic patients with recombinant human Erythropoietin is linked to a significant decrease in the gKv value towards the level of control TL. Altogether, the data demonstrate that patch-clamp studies on the Kv channels may provide a valuable tool delineating the role of the channels in TL cell-function and the pathogenesis of the diseases.