Abstract
Isolated scale melanophores of mosquitofish Gambusia affinis were examined to confirmwhether microtubules were concerned with pigment granule transport.
Single treatment of melanophores with keeping at room temperature after low temperature (-3 ?? -5°C) or with colchicine elicited rapid aggregation and dispersion in responses to epine-phrine and theophylline, respectively. The treatment of melanophores with low temperature blocked incompletely both melanosome aggregation and dispersion. Furthermore, these re-spouses were completely blocked by the combined treatment of the melanophores with low tem-perature-plus-colchicine. Under this combined treatment, the melanosomes remained in the fully dispersed state during the pretreatment. On the other hand, the same treatment to aggregated melanophores elicited incomplete dispersion of melanosomes during the pretreatment, indicating a dynamic function of microtubules in melanosome aggregation.
These results suggest that microtubules are essential to the transport of pigment granules also in mosquitofish melanophores.
