Dense‐core microtubules in neurons and gliocytes of the toad <i>Bufo arenarum</i> Hensel

Abstract Numerous microtubules of nerve cells and gliocytes in the toad are found, in electron micrographs, to contain a dense core. Such content is granular in nature, the granules being irregularly disposed in the lumen of the microtubules. Comparative observations on dense‐core microtubules in peripheral and central nerve cells indicate that they are consistent cell components in the entire nervous system of the toad. The functional significance of the granular content of the microtubles is discussed.