[Roentgen microanalysis demonstration of zinc in the gustatory system of the bullhead, Ameiurus nebulosus (Teleostei)].

The trace metal Zinc (Zn) seems to be essential for the normal functioning of the gustatory sense. In this study it was tried to localize Zn within the peripheral and central parts of the bullhead's gustatory system by the use of scanning electron microscopy and x-ray microanalysis. In freeze dried preparations of the bullhead's barbel taste buds (and the taste buds of rabbits) Zn is found in randomly distributed granules, which cannot be related to distinct taste bud regions. Furthermore, Zn occurs in sub-units of the central gustatory nuclei, the vagal and facial lobe of the rhombencephalon. Therefore Zn appears to be essential for intact peripheral as well as central gustatory processes, at least in lower vertebrates.