Immunohistochemistry of Salivary Enzymes and Morphology of Salivary Glands in Eurycea (Plethodontidae)

Although they potentially share ancestral heritage with the mental gland, salivary glands have not been studied thoroughly in plethodontid salamanders. Previous enzymatic studies in other families of amphibians have identified the presence of proteases and amylases, which are thought to be secreted from the intermaxillary gland and lingual gland. However, no such studies have been conducted in plethodontid salamanders, and the enzyme contents of these glands are poorly understood. We used immunohistochemistry to identify the presence of amylase, protease, and lipase in the glands of three species of Eurycea. Histological descriptions—based on hematoxylin and eosin staining—of the studied glands are also included. We found that amylase and protease were present in the intermaxillary gland and in the surface epithelium of the tongue. The lingual gland was notably lacking salivary enzymes. Preliminary results indicate the possible presence of lipase in the mouth of plethodontid salamanders. This study confirms the intermaxillary gland as a major salivary organ, while contrasting with the previous understanding of the amphibian lingual gland.