Histochemistry of mucosubstances in the frog respiratory epithelium

The histochemical nature of the mucosubstances of the respiratory epithelium of the frog palate was studied. 3 main types of epithelial cells were identified: Goblet cells which contained some glycogen, some neutral mucins and a mixture of sialidase-resistant and sialidase-labile sialomucins, non ciliated columnar cells with a secretory activity restricted to their apical pole. These cells contained abundant glycogen, some neutral mucins and sialidase-resistant sialomucins, ciliated cells with no secretory activity. The surface mucous blanket was composed of a mixture of predominant sialomucins and some neutral mucins. The histochemistry of mucosubstances in the respiratory epithelium of the frog palate differed from that of human and most respiratory systems by the presence of glycogen and the absence of sulphated mucins.