ovalbumin and cicutoxin

The effect of cicutoxin, the poisonous principle of the genus Cicuta, on K+ currents of activated T lymphocytes was investigated using the patch clamp technique. Cicutoxin produced a dose-dependent [5 x 10(-6) to 7 x 10(-5) mol/l] and completely reversible block of K+ currents with an EC50 of 1.8 x 10(-5) mol/l. A maximum block of 71% was achieved with cicutoxin at a concentration of 7 x 10(-5) mol/l. Since previous studies have shown that T lymphocyte proliferation is associated with K+ currents, the effect of cicutoxin on T lymphocyte proliferation was studied by means of 3H-thymidine uptake assays. At noncytotoxic concentrations [10(-7) to 5 x 10(-5) mol/l] cicutoxin reduced the 3H-thymidine incorporation dose-dependently. In conclusion, cicutoxin is a potent K+ current blocker which inhibits K+ channel-dependent proliferation of naive and memory T lymphocytes.

Topics: Alkynes; Animals; Concanavalin A; Diynes; Dose-Response Relationship, Drug; Fatty Alcohols; Kinetics; Lymphocyte Activation; Membrane Potentials; Molecular Structure; Ovalbumin; Patch-Clamp Techniques; Plant Lectins; Plants, Toxic; Potassium Channel Blockers; Potassium Channels; Rats; Rats, Inbred Lew; T-Lymphocytes; Toxins, Biological