Morphological and histochemical variations of mucous and oxynticopeptic cells in the stomach of the seps, Chalcides chalcides

Abstract

Mucous and oxynticopeptic cells in the gastric mucosa of the seps, Chalcides chalcides (Linnaeus, 1758) were examined by standard histochemical staining methods and by lectin histochemistry. The epithelial mucous cells lining the surface of the stomach and the mucous cells of the fundic glands elaborated mainly neutral glycoproteins with β(1,4)GlcNAc oligomers, GalNAc glycosidic residues and Galβ1,3GalNAc terminal sequences. The mucous cells of the fundic glands were stained specifically with the Paradoxical Con A method. The mucosecreting cells of the pyloric glands produced neutral glycoproteins, with β(1,4)GlcNAc oligomers, GalNAc residues and Galβ1,3GalNAc terminal sequences. Terminal L-fucose bound to the penultimate GlcNAc residues, and\or difucosylated oligosaccharides were also present. The pyloric glands did not stain with the Paradoxical Con A procedure. The morphology of the oxynticopeptic cells changes from the oral to the aboral region of the fundic mucosa. In the oral fundic tract the oxynticopeptic cells showed cytoplasm filled with zymogen granules, while in the aboral fundic region these cells contained few zymogen granules and showed cytoplasm full of empty vesicles, typical of the acid secreting cells. A secretion gradient of proteolytic enzymes and hydrochloric acid along the fundic mucosa of the seps can be hypothesised.

Histochemical and Immunohistochemical Analysis of the Stomach of Rhinella icterica (Anura, Bufonidae)

“…In R. icterica, the epithelial superficial cells produced galactose > galactosamine, being similar to those cells of Reptilia Chalcides chalcides [10]. Furthermore, galactose and -N-acetylgalactosamine were detected at apical domain of oxynticopeptic cells, that is, at the same localization as that of alcianophilic reaction.…”

“…Furthermore, galactose and -N-acetylgalactosamine were detected at apical domain of oxynticopeptic cells, that is, at the same localization as that of alcianophilic reaction. This result is probably peculiar to amphibians as R. icterica, Triturus carnifex [22], and other vertebrates, like seps (Chalcides chalcides) [10] and snake (Natrix natrix) [45], since epithelial cells exhibited very weak alcianophilic reaction. On the other hand, -Nacetylgalactosamine residue has been reported to bind specifically not only in the intracellular canaliculi and vesicular membranes of mammalian parietal cells [46][47][48] but also in oxynticopeptic cells of some nonmammalians, such as the green toad B. viridis [14] and the ruin lizard Podarcis sicula campestris [49].…”

“…In anurans, mucins are produced by goblet cells found in the esophagus and the intestines, but also by epithelial cells and mucous neck cells in the stomach [43]. In R. icterica, mucous neck cells of fundic region produce neutral glycoprotein, rich in galactose residues, similar to those of R. esculenta [19], Ceratophrys ornata [44], Ceratophrys chalcides [10], and reptile Natrix natrix [45].…”

“…Mucous cells have already been described in the stomach of mammals, as Rhesus monkey and baboon [11], as well as in other vertebrates as fishes [42] and lizards [10,18].…”

“…This mucous layer forms a highly viscous barrier that protects the stomach surface, being formed by acid and neutral glycoconjugates. Histochemical studies indicate differences regarding the qualitative expression of neutral, sulfated, and carboxylated mucosubstances [10,11]. The mucosubstances, which phylogenetically first appeared in mucous neck cells of the gastric glands of anurans [12], have already been reported for Rana aurora aurora [13], Bufo viridis [14], Rana perezi [15], Bufo melanostictus [3], and Bufo marinus [16], indicating variability among anuran species.…”