Halothane modifies colchicine binding to tubulin.

Tubulin extracted from rat brains was incubated at 37 degrees C with 3H-colchicine in the presence and absence of 28 mM halothane. The amount of 3H-colchicine bound to tubulin was reduced by nearly 50% at a colchicine concentration of 5 x 10(-5) M when halothane was present. At low (1 x 10(-7) M) and at high (1 x 10(-3) M) concentrations of colchicine, halothane did not affect the binding as much. The inhibition of colchicine-binding to tubulin by halothane appeared to be non-competitive.