Colchicine-inhibited cilia regeneration: explanation for lack of effect in tris buffer medium.

In Stentor coeruleus growth of new, daughter ciliates and experimentaly inducled regeneration of oral membranellar cilia are reversibly inhibited by low, nontoxic concentrations of colchicine. However, if the clulture medium containing colchicine (or Colcemid) is made up in tris(hydroxymethyl)aminomethane buffer, growth of ciliated daughters and regeneration of oral cilia proceed normally. The evidence suggests that the mechanism of this reversal of the effects of colchicine (or Colcemid) is due to a chemical reaction between tris(hydroxymethyl)-aminomethane (or its hydrochloride, or both) and colchicine (or Colcemid), wihich reduces the effective concentration of these mitotic spindle inhibitors reaching the stentors.