Histochemical analysis, smooth muscle immunolocalization and volumetric density of the elastic system fibres of the ostrich (Struthio camelus) phallus.

There are few scientific reports on the histology of the phallus of ratite birds. The aim of this study was to conduct a histochemical analysis to determine the distribution of smooth muscle cells and the volumetric density (Vv) of the fibres of the elastic system in the ostrich phallus. Adult ostriches, 14 months old, were used. The phalluses were fixed in Bouin's solution and then transferred to a buffered formalin solution. They were then processed using standard histological stains for paraffin and slices were obtained. The following techniques were performed: HE, Picrosirius red, Alcian Blue at pH 1.0 and 2.5. The Periodic acid-Schiff reagent and Weigert's Resorcin-Fuchsin with previous oxidation were performed. The M42 test system was used to quantify the elastic system fibres. For immunohistochemical analysis, an anti alpha smooth muscle actin monoclonal antibody was used. The surface of the phallus is covered by a non-keratinized stratified squamous epithelium, which becomes stratified cylindrical in the region of the spermatic sulcus. No glands associated with the connective tissue were observed. The Vv of the elastic system fibres was 4.75%. Smooth muscle cells were visualized only in the walls of blood vessels through immunostaining, with an absence in the lymphatic sinuses. Despite similarities with other birds, such as the presence of a fibrous external axis, a lymphatic core, and a spermatic groove, the ostrich phallus shows marked differences, including the absence of an elastic core, a non-keratinized lining epithelium, and the absence of glands throughout its extension.

An immunocytochemical study of the endocrine cells in the stomach and duodenum of Zonotrichia capensis subtorquata (Passeriformes, Emberizidae).

The main purpose of this study was to evaluate the regional distribution pattern and relative frequency of some endocrine cells in the three portions of the gastrointestinal tract (GIT)--the proventriculus, gizzard and duodenum- of the rufous-collared sparrow (Zonotrichia capensis subtorquata), by immunohistochemical methods using six types of polyclonal antisera, specific for serotonin (5-HT), somatostatin (D cells), glucagon, motilin, polypeptide YY (PYY) and insulin. In the proventriculus, endocrine cells immunoreactive for all of these markers were observed. The somatostatin-immunoreactive cells were found with greater frequency, with the presence of cytoplasmic processes. In the gizzard, endocrine cells secreting somatostatin, 5-HT and PYY were detected, while those secreting glucagon and insulin were not. In the final part of the gizzard, endocrine cells secreting 5-HT were more frequent, and cells secreting somatostatin and insulin were not detected. All of the cell types studied were observed in the duodenum in different frequencies, except for cells immunoreactive for glucagon and insulin. The somatostatin-positive (D cells) were the most numerous, being more prevalent in the intestinal glands. The other endocrine cells were identified in smaller numbers, some of them located in the intestinal villi and Lieberkuhn glands. The finding of these cell types in the duodenum confirms their preferential location in the final portions of the principal segments of the digestive system and suggests control by feedback of its functions. In conclusion, some interesting distributional patterns of gastrointestinal endocrine cells were found in this species of sparrow.

A comparative immunohistochemical study of endocrine cells in the digestive tract of two frugivorous bats: Artibeus cinerius and Sturnira lilium.

The purpose of the present study was to examine the serotonin (5-hydroxytryptamine, 5-HT), gastrin (GAS), cholecystokinin (CCK) and glucagon (GLUC) endocrine cells in the gastrointestinal tract of frugivorous Phillostomidae bats, Sturnira lilium and Artibeus cinerius, to clarify the correlation between distribution of cell types and their relative frequency, with feeding habits. Five portions of the gastrointestinal tract--fundus, pilorus, and three parts of the intestine, I, II and III--were examined. Most of the immunoreactive cells in the stomach and intestine were of triangular, oval or piriform shape. Serotonin-immunoreactive cells were most commonly found in the S. lilium intestine I (66.6+/-9.9) and the A. cinerius intestine III (35+/-18). Gastrin-immunoreactive cells were the most abundant cell type in the pyloric glands of both species. They were more numerous in A. cinerius (126.9+/-27.4) than in S. lilium (75.8+/-1.8). CCK-immunoreactive cells were found in the alimentary tract epithelia at moderate frequencies in both species. GLUC-immunoreactive cells were detected at very low or low frequencies. This study suggests that there is a correlation between endocrine cell distribution and frequency, and the feeding habits of the bats.