Fine structure of the oxynticopeptic cells in the gastric glands of the Ruin Lizard, Podarcis sicula campestris De Betta, 1857

The results of an ultrastructural investigation of the gastric glands of th e ruin lizard are reported. In this reptile the stomach can be divided into a larger fundus and a smaller pars pilorica. Fundic glands are characteriz ed by three main kinds of cells: mucous, endocrine, and oxynticopeptic; the latter were not observed in the pyloric glands. The morphological features of the oxynticopeptic cells change from the proximal to the distal region of the fundic mucosa. In the proximal region, numerous electron-dense secre tory granules, a well-developed granular endoplasmic reticulum, an evident Golgi complex, and a reduced system of smooth-surfaced vesicles and tubules in the apical cytoplasm characterize these cells. In the distal fundic reg ion, oxynticopeptic cells possessed numerous mitochondria and a well-develo ped smooth-surfaced endoplasmic reticulum, but secretory granules were rare . These data suggest the existence of a gradient in the production of prote olytic enzymes, and perhaps also of hydrochloric acid, along the oral-abora l axis of the stomach. The results are discussed with regard to the evoluti on of the gastric glands and of the digestive mechanism in vertebrates. (C) 2000 Wiley-Liss, Inc.