[Mechanism of the blocking of the centrosphere by substances similar to quinoline. Its prevention with spindle inhibitors similar to colchicine].

A colchicine-like substance, vincaleukoblastine (2.10-4M, 3 to 6 hours), prevents the blocking of the centrosphere which would be produced by quinoline or by a similar substance (glutaraldehyde), to the extent of the inhibition of polarity by this colchicine-like substance. This is interpreted as due to the fact that each molecule of colchicine-like substance binds to a single subunit (or heterodimer) of tubulin and consequently prevents the constitution of storage structures. It is supposed that on the contrary quinoline-like substances bind to several subunits of tubulin and that they can stabilize the storage structures, binding to them in several points. The ultrastructural study demonstrates that when the centrosphere is blocked by quinoline, there is accumulation, hypertrophy and permanence of the "dense bodies" later than prophase; sometimes they are fused in a large "dense mass". The "dense bodies", and perhaps the "striated bodies", may therefore be interpreted as constituting morphologically the storage structures, which enlarge when all the astral and spindle microtubules completely disappear by action of a quinoline-like substance.