The human major sublingual gland and its neuropeptidergic and nitrergic innervations.

BACKGROUND: What textbooks usually call the sublingual gland in humans is in reality a tissue mass of two types of salivary glands, the anteriorly located consisting of a cluster of minor sublingual glands and the posteriorly located major sublingual gland with its outlet via Bartholin's duct. Only recently, the adrenergic and cholinergic innervations of the major sublingual gland was reported, while information regarding the neuropeptidergic and nitrergic innervations is still lacking. METHODS: Bioptic and autoptic specimens of the human major sublingual gland were examined by means of immunohistochemistry for the presence of vasoactive intestinal peptide (VIP)-, neuropeptide Y (NPY)-, substance P (SP)-, calcitonin gene related-peptide (CGRP)-, and neuronal nitric oxide synthase (nNOS)-labeled neuronal structures. RESULTS: As to the neuropeptidergic innervation of secretory cells (here in the form of mucous tubular and seromucous cells), the findings showed many VIP-containing nerves, few NPY- and SP-containing nerves and a lack of CGRP-labeled nerves. As to the neuropeptidergic innervation of vessels, the number of VIP-containing nerves was modest, while, of the other neuropeptide-containing nerves under study, only few (SP and CGRP) to very few (NPY) nerves were observed. As to the nitrergic innervation, nNOS-containing nerves were very few close to secretory cells and even absent around vessels. CONCLUSION: The various innervation patterns may suggest potential transmission mechanisms involved in secretory and vascular responses of the major sublingual gland.

Prostate-specific antigen: An unfamiliar protein in the human salivary glands.

OBJECTIVES: The presence of prostate-specific antigen (PSA) in saliva and salivary glands has been reported. Nevertheless, its release pathway in these glands remains to be elucidated. Here, we showed PSA subcellular distribution focusing on its plausible route in human salivary parenchyma. MATERIALS AND METHODS: Sections of parotid and submandibular glands were subjected to the immunohistochemical demonstration of PSA by the streptavidin-biotin method revealed by alkaline phosphatase. Moreover, ultrathin sections were collected on nickel grids and processed for immunocytochemical analysis, to visualize the intracellular distribution pattern of PSA through the observation by transmission electron microscopy. RESULTS: By immunohistochemistry, in both parotid and submandibular glands PSA expression was detected in serous secretory acini and striated ducts. By immunocytochemistry, immunoreactivity was retrieved in the cytoplasmic compartment of acinar and ductal cells, often associated with small cytoplasmic vesicles. PSA labeling appeared also on rough endoplasmic reticulum and in the acini's lumen. A negligible PSA labeling appeared in most of the secretory granules of both glands. CONCLUSIONS: Our findings clearly support that human parotid and submandibular glands are involved in PSA secretion. Moreover, based on the immunoreactivity pattern, its release in oral cavity would probably occur by minor regulated secretory or constitutive-like secretory pathways.

Antennular Morphology and Contribution of Aesthetascs in the Detection of Food-related Compounds in the Shrimp Palaemon adspersus Rathke, 1837 (Decapoda: Palaemonidae).

Shrimp are an essential ecological component of marine ecosystems, and have commercial importance for human consumption and aquaculture. Like other decapod crustaceans, shrimp rely on chemical senses to detect and localize food resources by means of chemosensilla that are located mainly on the cephalothoracic appendages. Using the shrimp Palaemon adspersus, a model organism with omnivorous feeding behavior, we aimed to provide comparative information on the role of aesthetascs, antennular sensilla, and flicking behavior in food detection. To this end, we examined i) the morphology of antennular sensilla by field emission scanning electron microscopy, ii) the shrimp's sensitivity to a number of food-related compounds (amino acids and sugars) by means of whole-animal bioassays, and iii) the contribution of the aesthetasc sensilla to food detection. Our results showed that, aside from the aesthetascs, only three other main morphotypes of setae with chemoreceptive features were present in the antennules, thus accounting for relatively simple sensillar equipment. Nevertheless, we found broad-spectrum sensitivity of the shrimp to a number of amino acids (i.e., isoleucine, leucine, methionine, phenylalanine, glycine, tryptophan, cysteine, and tyrosine) and carbohydrates (trehalose, maltose, cellobiose, and fructose) that was consistent with the omnivorous or scavenging habits of the animal. Although aesthetasc ablation attenuated flicking behavior in a chemical stimulus-independent manner, success in detection and short-range localization of food did not rely on the presence of aesthetasc sensilla. This finding confirms the existence of a non-aesthetasc alternative pathway for feeding, with functional redundancy in simple generalist feeder models such as shrimp.

Animal models are reliably mimicking human diseases? A morphological study that compares animal with human NAFLD.

Non-alcoholic fatty liver disease (NAFLD) is a clinical-pathological syndrome that includes a wide spectrum of morphological alterations. In research, animal models are crucial in evaluating not only the pathogenesis of NAFLD and its progression, but also the therapeutic effects of various agents. Investigations on the ultrastructural features of NAFLD in humans are not copious, due to the difficulty to obtain human samples and to the long time of NAFLD to evolve. Translational comparative studies on the reliability of animal models in representing the histopathologic picture as seen in humans are missing. To overcome this lack of investigations, we compared the ultrastructural NAFLD features of an animal model versus human. Sprague-Dawley rats were fed with a high fat diet (HFD) for 1-4 weeks, while control rats were fed with a standard diet. Human specimens were collected from patients with diagnosed fatty liver disease, undergoing liver biopsies or surgery. Rat and human samples were examined by light microscopy and by transmission and high resolution scanning electron microscopy. The present work demonstrated that NAFLD in animal model and in human, share overlapping ultrastructural features. In conclusion, animal HFD represent an appropriate tool in studying the pathogenesis of NAFLD.