A light and electron microscopic study of the epithelium of the extrapulmonary airways of Mauremys caspica and Lacerta lepida (Reptilia).

The epithelium of the extrapulmonary airways of a Chelonia (Mauremys caspica) and a Squamata (Lacerta lepida) was investigated by means of conventional light and transmission electron microscopy, scanning electron microscopy, histochemistry and immunocytochemistry. The epithelium of Mauremys caspica is composed of basal, ciliated, endocrine and mucous cells. Serotonin-immunoreactivity was detected in the endocrine cells. Mucous cells were found to contain either sialo-mucins or both sialo- and sulphomucins. The extrapulmonary airways of Lacerta lepida were lined by an epithelium composed of basal, ciliated and secretory cells. No endocrine cells were detected. Secretory cells showed a different morphology to that observed in the mucous cells of Mauremys caspica suggesting a possible serous role for these cells. Migratory cells (plasma and mast cells, leucocytes and macrophages) and small intraepithelial nerves were also detected within the epithelium of both species. The present results show that marked morphological differences occur between the epithelia of the extrapulmonary airways of reptiles belonging to the genus Chelonia and Squamata.