THE ROLE OF MICROTUBULES IN THE MOVEMENT OF PIGMENT GRANULES IN TELEOST MELANOPHORES

Abstract
When microtubules in teleost melanophores are disrupted with antimitotic agents, colchicine, high hydrostatic pressure, low temperature, and vinblastine, the alignment and movement of the pigment granules in these cells disappear; during recovery, the return of alignment and movement corresponds in both time and space with the repolymerization of microtubules. Furthermore, analysis of nearest neighbor distances in untreated melanophores reveals that pigment granules are closely associated with microtubules. Other structures such as microfilaments, the endoplasmic reticulum, and the cytoplasmic matrix do not appear to be involved. Thus we conclude that microtubules determine the alignment and are essential for the selective movements of the pigment granules in these cells.