Distribution of mucins in the mucosa of the digestive tract of reptiles: a histochemical study.

In the present study, the distribution and characteristics of mucins in the digestive tract of 3 reptiles (Lacerta lepida, Mauremys caspica and Testudo graeca) are investigated. In the esophagus of Testudo graeca, both the glands and the mucous cells of the surface epithelium contained sulphosialo-mucins. In Lacerta lepida, esophageal mucous cells contained either-sialo-mucins or sulphosialo-mucins. The esophageal mucous cells of Mauremys caspica contained acidic mucosubstances. The stomach of the species studied revealed a small amount of acidic mucosubstances; in Lacerta lepida and Testudo graeca, abundant neutral mucins were detected. In the intestine, the amount of acidic mucosubstances was increased in a caudal direction, the sulphosialo-mucins being predominant. In conclusion, acid mucins were more abundant in the esophagus and intestine than in the stomach. This may be related to cytoprotective roles in the esophagus and protection against potential pathogens in the intestine.