MORPHOLOGICAL AND FUNCTIONAL CHARACTERISTICS OF THE INTRAMURAL NEURAL APPARATUS OF THE DUODENUM IN INTACT RATS

Bilinskyi I. I., Popovych Yu. I., Fedorak V. M.

MORPHOLOGY

Scentific article

Background. Within the wall of the duodenum, there is the intramural neural apparatus between its various layers, which is histologically presented as the following three plexuses: the subserous, the myenteric, andthe submucosal ones. As the myenteric plexus, which is located between the longitudinal and circular layers of smooth duodenal myocytes and is found in the duodenum, is the most significant one, it became an object of our attention. The aim of the study was to establish morphological and functional characteristics of nerve cells of the duodenal myenteric plexus in intact rats using light-optical and ultrastructural techniques. Methods. The study was carried out on 15 white outbred sexually mature male rats. The histological sections were stained according to the Nissl method with 0.5% cresyl violet aqueous solution. The morphological assessment of the state of nerve cells was conducted and the degree of their changes was determined. The ultrastructural study of the material was carried out using the TEM-125K electron microscope (Selmi, Ukraine) at an accelerating voltage of 75 kW, followed by photographing at magnifications from 1,600 to 16,000 times. Results. According to the light-optical and electron microscopicstudies, within the myenteric plexus of the duodenum, the most common neurons were those with a typical structure, unchanged, making up 79.50% in the proximal part and 81.00% in the distal part of the duodenum. Both undifferentiated neurons and nerve cells with morphological changes in the organelles were rarely seen. Focal chromatolysis, nuclear and nucleolar ectopy, which are regarded as reversible changes, were detected in 18% of neurons in the proximal duodenum and 16.5% of neurons in the distal duodenum, while massive cytoplasmic vacuolization, total chromatolysis, drastic neuronal shrinkage or severe neuronal swelling, karyopyknosis and karyolysis, which are regarded as irreversible changes, were detected in 2.5% of neurons in both duodenal portions. The degree of neuronal changes equaled to (40.23% and 38.40%). Conclusions. In the myenteric plexus of the duodenum in intact rats, unchanged neurons predominated. Among altered neurons, nerve cells with reversible changes were more frequentlyfound; only a few of them were irreversible.

intramural neural apparatus, duodenum, myenteric plexus, neurons.

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«Bulletin of problems biology and medicine» Issue 3 (161), 2021 year, 240-244 pages, index UDK 616-076.4+591.48+616.342+616-092.9

10.29254/2077-4214-2021-3-161-240-244