THE EFFECT OF COLCHICINE ON MIGRATION OF PIGMENT GRANULES IN THE MELANOPHORES OFFUNDULUS HETEROCLITUS

Abstract

1. The effects of colchicine were studied on pigment migration in melanophores of the killifish, Fundulus heteroclitus. 2. Pretreatment of the melanophores in colchicine resulted in a decrease in the rate of melanin aggregation in response to epinephrine. The rate of response depended upon the length of pretreatment and the concentration of colchicine. 3. Colchicine produced dispersion of pigment in punctate epinephrine-treated melanophores which was greater than that produced by Ringer alone. 4. Cysteine reversed the effect of colchicine on the response of melanophores to epinephrine. This reversal depended upon the concentration of cysteine used. 5. The mechanism of action of colchicine is unclear but is discussed in relation to possible effects on cytoplasmic viscosity and microtubules.