EN
Ryanodine treatment - a plant alkaloid known to be a powerful inhibitor of muscle contraction - changes the ionic selectivity and conductance of several types of K+ channels in muscle cells. Available data provide evidence that the effects of ryanodine on K+ channel properties are not secondary to Ca2+ release from sarcoplasmic reticulum, but result from a direct interaction of the alkaloid with the channel protein. In the present investigations we applied the whole-cell patch-clamp technique to study ryanodine effects on the properties of Kv1.3 channels, which are present in lymphocytes and rat brain cells. The effects of ryanodine applied in the concentration range 10-5-10-4 M on the ionic selectivity, conductance, gating and kinetics of Kv1.3 channels expressed in human T lymphocytes were examined. Our data provide evidence that none of these properties was changed upon ryanodine treatment. Altogether, our data support the notion that Ryanodine may interact with various types of K+ channels differently. The different response to Ryanodine treatment might be another pharmacological feature delineating differences among various types of K+ channels.