The occurrence of serotonin-containing cells in the esophageal epithelium of the bullfrog Rana catesbiana

Summary Fluorescence histochemical examination of biogenic amines of the frog esophageal mucosa revealed that a serotonin-like monoamine exhibiting an yellow fluorescence was present in a certain type of cells. The new type of cells was specifically stained by the immunohistochemical method using anti-serotonin antiserum. From these observations, it is suggested that the new cell type in the esophageal mucosa probably contains 5-hydroxytryptamine (serotonin). The serotonin-containing cells were argentaffin, but negative for Grimelius' silver stain.