The use of tetracycline hydrochloride as a rapid fluorescent stain for myelin membranes in vertebrates and invertebrates.

We report here the use of tetracycline as a fast and reliable histological stain of myelinated nerves. These results are significant in that they point to tetracyclines as potentially important probes to study the role of divalent and trivalent cations in myelinated nerves. The usefulness and specificity of tetracycline as a supravital probe for calcium and iron metabolism in myelinated nerves is currently under study.