Microscopic study of rat pancreas after sympathectomy

The aims of the study are to monitor the structural changes in the rat pancreatic tissue after surgical sympathectomy and assess its effect on the pancreatic endocrine function. Twelve animals were used in this study. All animals had surgical sympathectomy. The morphological changes of the islets of Langerhans and the pancreatic acini were studied under the light microscope, 2 and 3 weeks after surgery. Glucose tolerance test and fasting blood sugar levels were monitored at different intervals of time after sympathectomy. The microscopic examination of the pancreatic tissue after sympathectomy showed histological changes, in the form of general atrophy and pancreatic cell degeneration. Furthermore, the fasting blood glucose levels and the glucose tolerance tests were significantly increased. The results of this study demonstrated that the pancreatic function in rats is dependent on the sympathetic innervations,and the metabolic and histologicalabnormalities were observed after surgical sympathectomy. The structural changes in the pancreatic acini and the islets of Langerhans after vagotomy and sympathectomy may explain the failure of pancreatic cell transplantation and the metabolic abnormalities that accompany the neurogenic shockin humans

Ultrastructure of the ferret nodose ganglia

The Nodose gangalia of two male and two female adult ferrets were examined using electron microscopy. The nodose ganglion appeared as a very compact structure completely surrounded by a connective tissue capsule, occupied by nervous and glial elements and also by bundles of nerve fibers. The nerve cells with large nucleus and with one or two prominent nucleoli were recognized, and each had an intact and irregular cell membrane envelope. The nerve cells were surrounded by glial cells which were recognized by their shape and darkly stained nuclei. The common feature of the nerve cell cytoplasm was lysosome like dense bodies, clusters of ribosomes and numerous mitochondria. Myelinated and unmyelinated axons were seen between the nerve cells, among them the dense nuclei of Schwann cells were observed. No synaptic contact between the axons and the nerve cells or vesiculated axon profiles were observed in the ferret nodose ganglion, so the nerve cells are pseudounipolar type which are similar to the nodose ganglia of man and other experimental animal species. No sexual dimorphism was observed in the ferret nodose ganglion. Therefore, the ferret nodose ganglion is recommended for use in laboratory studies, concerned with the central and peripheral connections of the ganglion

Electron microscopic and autoradiographic studies of the myenteric ganglia of the ferret stomach after highly selective vagotomy

In this study, the preganglionic fibres of the vagus nerve were investigated in the myenteric ganglia of the ferret stomach three and four months after highly selective vagotomy. Autoradiographic technique at the electron microsscopic level was used to analyze the vagal nerve terminals after injection of tritiated leucine as an anterograde labeling tracer into the vagal dorsal motor nucleus. Electron microscopic examination of the body of the stomach of control animals showed normal ulrastructure of the myenteric ganglia and labeled nerve fibres were seen distributed in the myenteric ganglia of the body and pyloric areas of the stomach. In the acute experimental animals injection of tritiated leucine was carried out immediately after surgery. After 48 hours survival period, electron mictoscopic examination of the body of the stomach showed no morphological changes, and no labeled nerve fibres as a results of highly selective vagotomy while the pylorus showed many labeled nerve fibres. In the chronic experiments, the animals were left to survive for three months after highly selective vagotomy. After injection of tritiated leucine and analysis by autoradiography, two important findings were observed in the denervated areas of the body of the stomach [i] Morphological changes affecting the ganglionic cell bodies, axons and nerve terminals [ii] Re-appearance of labeled nerve fibres in the body of the stomach. Interstingly, electron microscopic examination of the same areas of the body of the stomach four months after highly selective vagotomy showed normal ultrastructure of the myenteric ganglia with labeled nerve fibres in the same areas. It is concluded that the deprivation of the preganglionic input to the myenteric ganglia produced trans-synaptic neurological changes. These morphological degenerative changes disappeared when the stomach was re-innervated. Re-appearance of the labeled nerve fibres in the denervated areas of the stomach is due either to regeneration of the cut branches of the vagal nerve or due to the sprouting of the intact vagal nerve terminals which spread from the pyloric areas to innervate the denervated areas of the body of the stomach. This phenomenon of sprouting of the intact vagal nerve terminals or regeneration of the cut nerves, which was demonstrated by autoradiography at the electron microscopic level may explain the recovery of gastric function after vagotomy and may account for the failure of vagotomy for the treatment of peptic ulcer patients. It also could reduce the need for surgical intervention in peptic ulceration

Sprouting of the vagus nerve after highly selective vagotomy: an autoradiographic study in the ferret stomach

In this study, the sprouting of the vagal nerve terminals were investigated in the ferret stomach after highly selective vagotomy by using the autoradiographic technique. The acute experimental animals which had highly selective vagotomy were injected immediately with tritiated leucine into the vagal dorsal motor nucleus. autoradiographic examination of the body of the stomach failed to show any labelled nerve fibres, while the pylorus showed many labelled nerve fibers. These observations indicate that the highly selective vagotomy has been performed successfully. Abdominal examination, of the chronic experimental animals, three months after highly selective vagotomy. bridges of scar tissue were observed by passing the vagotomy ligatures to supply the stomach. Histological examination of the regrown tissue showed that it was normal nerve fibres. After cutting this regrown tissue and injection of these chronic animals with tritiated leucine into the vagal dorsal motor nucleus, labelled nerve fibres were seen in the body of the stomach. This indicates that terminals reactive sprouting of the vagus nerve has spread from the pylorus to supply the body of the stomach. This phenomenon of the compensatory reactive sprouting of the vagal nerve terminals may explain the recovery of gastric function and may account for the failures of highly selective vagotomy in humans. However, modification of surgery may decrease the high rate of incidence of recurrent peptic ulcer after highly selective vagotomy