Comparative neurohistological observations on the pancreatic duct in certain birds and mammals as revealed by cholinesterase technique

A comparative study of pancreatic duct innervation of Francolinus pondicerianus (grey partridge or safed teeter) and Suncus murinus (Indian musk shrew) as revealed by cholinesterase technique has been done for investigation. In Suncus pancreas, the AChE-positive ganglia, elongated and irregularly shaped, medium and large-sized, were recorded either on the periphery of the excretory duct or on the wall of the duct. No ganglia were recorded on the periphery, although the fibres of the ganglia were in close association with the periductular plexus and the fibres of the peri-insular plexus in Francolinus. In Suncus, multipolar and AChE-positive ganglia of various shapes, arranged in chain-like fashion on the duct, were recorded, whereas in Francolinus the multipolar ganglia of AChE-positive nature and of various shapes, arranged in chain-like fashion, were observed in the duct region.     

Fluorescence histochemical observations on the intrinsic adrenergic innervation and monoamine-containing cells of the feline pancreas,with special reference to the terminal main pancreatic duct of wirsung

Summary Intrinsic adrenergic innervation of the pancreas of the cat was studied using two fluorescence histochemical methods. Special emphasis was focused on the monoaminergic regulation of the mechanisms responsible for dynamically active suction-pressure pumping at the choledocho-pancreatico-duodenal junction, consisting of a labyrinthine reservoir chamber surrounded by a contractile mantle of smooth muscle, described recently (Kyösola, 1976). In that junction area, a rich distribution of single varicose fluorescing nerve fibers and small nerve fascicles, both free (i.e., unrelated to the blood vessels) and forming typical perivascular nerve plexuses, as well as large ganglia of nonfluorescing nerve cells surrounded by fluorescing baskets of varicose nerves were observed in the connective, fat, and pancreatic tissues, as well as between the smooth muscle bundles of the contractile smooth muscle mantle surrounding the reservoir chamber and its minor compartments. The epithelial lining of the labyrinthine duct system contained some solitary brightly yellow fluorescing enterochromaffin cells. In addition, two other categories of fluorescing cells were observed: (1) Small rounded cells with a relatively large rounded nucleus, and exhibiting a clearly bluish, usually granular, fluorescence varying from weak to intense; (2) Larger cells exhibiting quite a weak, clearly greenish to greenish-yellow fluorescence, either gathered in homogeneous clusters or mingled with the cells of the former type into heterogeneous cells clusters. These two cell types were clearly distinguishable from each other, but intermediate cell types were also seen. Thus, a continuous scale of fluorescing cells was observed, the color of the fluorescence varying from clearly bluish to greenish-yellow, the intensity of the fluorescence varying from intense to weak (respectively, in general), and the size ranging from small to large (respectively). These cells, probably heterotopic alpha cells of the islets of Langerhans, were frequently in quite close proximity to the smooth muscle surrounding the contractile labyrinthine system or its minor compartments. On the other hand, they were frequently in close proximity to quite large thin-walled sinusoid-type blood vessels. At least some of these fluorescing cells were surrounded by fluorescing varicose nerves, suggesting the existence of a neuroendocrine link. Scattered among these fluorescing cells, and also gathered into small clusters, were nonfluorescing nerve cells interconnected with fluorescing varicose nerves. The fluorescing cells of the endocrine pancreas, similarly, could be arbitrarily classified into two main categories, although intermediate cell types were observed as well: (1) Small rounded cells with a large, ovoid to rounded, centrally placed nucleus, and exhibiting a moderate to intense granular cytoplasmic fluorescence. The color of the fluorescence varied from yellow-green to blue-green, and there were considerable differences also in the fluorescence intensity. (2) Mixed irregularly with the type (1) cells were cells with more or less the same cytologic characteristics, but slightly larger, and exhibiting a rather homogeneous weak yellow fluorescence. Sometimes the fluorescence intensity was so weak that it was hardly discernible. These cells were packed densely and irregularly with the type (1) cells within the clusters, and no clear-cut spatial organization between these two cell types was observed. In the wall of the main pancreatic duct of Wirsung, both free and perivascular fluorescing nerves were seen within the different layers, including the (distally incomplete) smooth muscle layer. The epithelial lining of the duct contained enterochromaffin cells, sometimes located so deeply in the epithelial invaginations that they were in close proximity to the smooth muscle. The distribution of fluorescing nerves in the exocrine pancreas was sparse. Typical enterochromaffin cells exhibiting a bright yellow granular cytoplasmic fluorescence were scattered either solitarily or in small groups in the epithelial lining of the acini and of the small excretory ducts. Blue-green fluorescing varicose adrenergic axons were some-times seen to connect enterochromaffin cells or groups of them located in different acini. Scattered within the parenchyme of the exocrine pancreas were clusters of nonfluorescing nerve cells surrounded by typical baskets of fluorescing varicose terminal ramifications of adrenergic axons. In the endocrine pancreas, similarly, only a relatively sparse distribution of fluorescing nerves was observed among the islet cells and surrounding clusters of them. However, groups of islet cells were observed to be interconnected by fluorescing varicose nerves coursing through or near nonfluorescing ganglia, suggesting an integrative neural connection between pancreatic islets and nonadrenergic ganglia via adrenergic nerves.     

First-ever marine mammal and bird observations in the deep Canada Basin and Beaufort/Chukchi seas: expeditions during 2002

Wildlife observers recorded the presence and distribution of birds and marine mammals along the cruise tracks of oceanographic expeditions in the Canada Basin, Beaufort Sea and Chukchi Sea during 2002. A total of 74 marine or marine-associated mammals were recorded, representing seven species. A total of 1,213 birds, representing 16 species, were recorded. The surveys took place during a combined 208 h of observation on the Louis S. St. Laurent and the RV Mirai between 16 August and 6 October 2002. The distribution of marine mammals and birds along the cruise tracks was clumped, with species tending to occur in proximity and in areas where productivity is enhanced due to oceanographic features (e.g. submarine canyons, areas of coastal upwelling, shelf break). Few species were observed in the deep Canada Basin. Polar bears and walruses appeared attracted to the ships, while belugas may have avoided them.     

Anatomical and neurohistological observations on the tongue of the India goat, Capra aegagrus.

The anatomy and neurohistology of the tongue of the Indian goat, Capra aegagrus, have been described. The apex linguae is notched in the centre. The foramen caecum is found to be absent. The sublingua could not be traced. The filiform papillae are the most common and divided into three types: the simple, giant, and true filiform papillae. The true filiform papillae are the most developed of the three types. The foliate papillae are absent. There are 13--14 circumvallate papillae arranged in two rows in a V-shaped pattern. The fungiform papillae are large and could easily be seen with the naked eye. They are scattered over the entire dorsum, being in abundance at the tip. The tongue of the goat is richly innervated. On the dorsum, the lamina propria is innervated by thick nerve fibres. In the fungiform papillae quite a large number of nerve fibres could be seen. The circumvallate papillae are also abundantly provided with nerves. A few ganglion cells are found below the circumvallate papillae. Thick nerve fibres are seen across the numerous glands and their ducts. Muscle fibres and connective tissue are also richly innervated.     

Anatomical, neurohistological and histochemical observations on the tongue of Francolinus pondicerianus (grey partridge or safed teeter).

The staining and demonstration of neural elements in relation with other associated structures was most satisfactory at pH 5.2, incubation period 20 h, and temperature 40degreesC. Ganglia of various shape and size were observed on or near the fungiform, filiform and foliate papillae. In the region of the fungiform papillae, a chain of ganglia (parasympathetic) was observed. The nerve cells of these ganglia showed cholinesterase (ChE) activity. The neural networks of the foliate papillae were connected with the neural terminal network and occasionally to the ganglia. The innervation of blood vessels (artery and vein) was profuse. At times ganglia were noticed on the periphery of the artery. Neuromuscular spindle-like structures were noticed occasionally. Dot-like free nerve endings were also observed. The ChE activity was very marked in the muscle fibres lying in the region of the circumvallate papillae but was less marked in the muscle fibres lying in the region of the filiform and fungiform papillae.     

Neurohistological observations on the oesophageal innervation of rabbit

Summary The vegetative, motor, and sensitive innervation of the oesophagus of rabbit was studied by means of several neurohistological techniques. A great deal of vegetative and somatic nervous formations were found and described within the various segments of the organ; namely at level of the cervical, thoracic, prediaphragmatic, and abdominal oesophageal tracts. In particular, isolated and grouped ganglion cells, interstitial and associative neurons, free nervous terminations, and an amyelinated subepithelial network sending delicate fibrils to the basal layers of the impending epithelium were described. The vegetative nervous component is organized into an extramural oesophageal plexus, and into an intramural one. The numerous motor endplates lying on the striated muscle fibres show different forms and several other structural pecularities. The sensitive terminations are represented by simple and non-capsulated Ruffini's corpuscles contained within the submucous connective tissue. The possible functional correlations of these morphological findings are discussed.This study was in part supported by a grant from the Italian C. N. R.     

Ontogeny of intrinsic innervation in the human thymus and spleen.

The ontogeny of the innervation of human lymphoid organs has not been studied in detail. Our aim was to assess the nature and distribution of parenchymal nerves in human fetal thymus and spleen. We used the peroxidase immunohistochemical technique with antibodies specific to neuron-specific enolase (NSE), neurofilaments (NF), PGP9.5, S100 protein, and tyrosine hydroxylase (TH) and evaluated our results with image analysis. In human fetal thymus, NSE-, NF-, S100-, PGP9.5-, and TH-positive nerves were identified associated with large blood vessels from 18 gestational weeks (gw) onwards, increasing in density during development. Their branches penetrated the septal areas at 20 gw, reaching the cortex and the corticomedullary junction between 20 and 23 gw. Few nerve fibers were seen in the medulla in close association with Hassall's corpuscles. In human fetal spleen, NSE-, NF-, S100-, PGP9.5-, and TH-positive nerve fibers were localized in the connective tissue surrounding the splenic artery at 18 gw. Perivascular NSE-, NF-, S100-, PGP9.5-, and TH-positive nerve fibers were seen extending into the white pulp, mainly in association with the central artery and its branches, increasing in density during gestation. Scattered NSE-, NF-, S100-, PGP9.5-, and TH-positive nerve fibers and endings were localized in the red pulp from 18 gw onward. The predominant perivascular distribution of most parenchymal nerves implies that thymic and splenic innervation may play an important functional role during intrauterine life.     

Sources of the innervation of the carotid reflexogenic zone in representative reptiles

The investigation is dedicated to study sources of the carotid reflexogenic zone innervation in 43 tortoises (Testudo horsfieldi and Emys orbicularis). In 7 tortoises fine preparation of the vessels and nerves of the cervical area after V. P. Vorob'ev has been performed. In 13 animals descending branch of the glossopharyngeal nerve has been resected. In 4--the caudal ganglion of this nerve and in 9 tortoises the caudal ganglion of the vagus nerve have been resected. In 10 tortoises adrenergic nervous plexuses are studied after Falck-Govyrin method, and cholinergic ones--after Karnovsky-Roots. As demonstrate anatomical investigations, to the carotid reflexogenic zone of the tortoises, situating in the area of the common carotid artery base, the branches of the glossopharyngeal and of the vagus nerve approach. The experiments with resection of these nervous conductors demonstrate that by the end of 3 days after the operation myelin nervous fibers of various thickness are at the stage of granular decay. Cholinergic and adrenergic nervous fibers and plexuses are revealed histochemically in the carotid zone.