Морфологична характеристика на миентеричния сплит и неврохимични аспекти на неадренергична и нехолинергична трансмисия в коло-ректалната област на плъх // Morphological characteristics of the myenteric plexus and neurochemical profile of the nonadrenergic, noncholinergic transmission in the colorectal region of the rat
Зареждане...
Дата
2022
Автори
Киров, Тодор Валентинов // Kirov, Todor Valentinov
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Издател
Медицински университет - София // Medical University - Sofia
Резюме
ЦЕЛ И ЗАДАЧИ
Целта на настоящото изследване е да се установи морфологичната организация на МС и неврохимичните особености на неадренергичната и нехолинергична трансмисия в коло-ректалната област на плъх.
За осъществяването на тази цел, ние си поставихме следните задачи:
1. С помощта на класически хистологични техники да установим нормалната морфология на МС в КРО на плъх.
2. Чрез използването на витални оцветители да определим цитоархитектониката на невроналните структури на МС.
3. Чрез ензимохистохимични методи да се докаже наличието на нитрергични неврони в МС.
4. Посредством светлинномикроскопски имунохистохимични реакции да се установи неврохимичната принадлежност на ентералните неврони към нитрергични, пептидергични и пуринергични субпопулации в МС.
5. Да се направи сравнителен статистически анализ на установените неврохимични находки по хода на КРО.
6. На основата на получените данни да се направи комплексен анализ на неврохимичния профил на миентералните неврони с акцент върху NANC трансмитерите, използвани от тях.
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SUMMARY
The enteric nervous system (ENS) exerts local control on the gastrointestinal motility, exocrine and endocrine secretions, local blood flow, and modulates the immune and inflammatory processes in the gut. One of its two principal components, the myenteric plexus is closely involved in the reflex regulation of contractile activities of the surrounding intestinal musculature. As opposed to the classical paradigm, that the major transmitters of such autonomic neurons are acetylcholine (ACh) and noradrenaline there has been no convincing evidence that noradrenaline plays any role in the intrinsic neurotransmission of the ENS. Consequently, over time the nonadrenergic, non-cholinergic (NANC) transmission system, comprising the entirety of other transmitters, was proved much more diverse and complex. The current knowledge on the intestinal part of the myenteric plexus is primarily based upon gastrointestinal research on the small intestine of the guinea pigs as models for humans. However, rodents such as the rat are the most commonly used species for biomedical research because they are very similar to humans genetically. Therefore, the aim of this study was to investigate the morphology of the myenteric plexus and describe the neurochemical coding of adult rat myenteric neurons in the large intestine with a special emphasis on NANC transmitters. The general morphology, cytoarchitecture and morphometric properties of the myenteric plexus in the rat colorectal region appeared to mimic its equivalent in the more proximal parts of the rat digestive tract and in other experimental animals. The main neuroactive substances involved in the NANC transmission are nitric oxide (NO), tachykinins, mostly substance P (SP) and adenosine triphosphate (ATP), co-localized in variable proportions with other neuroactive substances. After applying NADPH-diaphorase enzyme histochemistry and nNOS immunohistochemistry, we were able to demonstrate numerous nitrergic somata of myenteric neurons with Dogiel type I morphology. In addition to the observed nitrergic distributional patterns, significant variations were registered in the staining intensity of myenteric structures in the colon and anorectal area. Tachykinins and more precisely their major representative SP formed an abundance of intensely stained varicose SP immunopositive fibers, ensheathing the immunonegative myenteric neuronal cell bodies in a basket-like manner. ATPergic structures were mostly limited to fiber bundles surrounding unstained myenteric neurons and penetrating the two muscle layers. A notable finding was the notable presence of reactive nerve fiber bundles in the longitudinal muscle layer. Our results suggest that myenteric neurons in the distal intestinal portion utilize a broad spectrum of enteric transmitters, including classical and NANC transmitters.
Описание
Ключови думи
анатомия; храносмилателна система - физиология; неврофизиология; синаптична трансмисия; вегетативна нервна система - физиология; ентерична нервна систем; миентеричен плексус; миентеричен сплит // , anatomy; digestive physiology; neurophysiology; synaptic transmission; autonomic nervous system - physiology; enteric nervous system; myenteric plexus