NEURONAL SYNCYTIA IN THE ENTERIC NERVOUS SYSTEM OF THE FELIS CATUS

Syncytial connections between neurites were found using electron microscopy in the nervous system of cats, young pigs, as well as in the culture of mollusk ganglia cells. The possibility of detecting neural syncytia using the method of the unmasking of digital images of arborizations of interneuronal connections in the nervous tissue of the brain was established, but this method was not used to study of the enteric nervous system. The aim of the study was to analyze the submucosal and intermuscular autonomic nerve plexuses of the intestine of the domestic cat (Felis catus) by method of the unmasking of digital images. The material for the study was preparations of the small and large intestines. All manipulations with animals were carried out in compliance with Directive 2010/63/EU of the European Parliament and of the Council of the European Union on the protection of animals used for scientific aims. The experiments were carried out on mature outbred cats (n=45). To obtain preparations, the intestinal vessels of experimental animals were sequentially perfused with solutions of barium hydroxide, then silver nitrate, and hydroquinone. After perfusion, intestinal preparations were taken and fixed. The obtained histological preparations (including ultramicroscopic ones) were studied by the method of unmasking of digital images (of the downscaling of the image resolution). As a result of the study, numerous distant syncytial anastomoses connecting the bodies of neurocytes of all types of Dogiel cells were revealed for the first time, and their properties were established. Widespread multiple morphological mono- and polyvalent ring syncytial structures were found. Their supposed function is the opposite direction of electric and axoplasmic flow. An in vivo feature of the reflex syncytial apparatus of the enteric nervous system is the formation of multi-tiered closed loop-like contacts of nerve fibers and type II Dogiel cells with pronounced local and diffuse receptor branches. Thus, a characteristic feature of the enteric nervous system is the presence of multicellular connections of neurocytes in the form of a network of distant syncytial anastomoses. These anastomoses are real proof of the reticular principle of the structural organization of the autonomic plexuses of the enteric nervous system and the reticular concept in general.

1. Shvann T. Mikroskopicheskie issledovaniya o sootvetstvii i strukture i roste zhivotnykh i rasteniy. M.-L.: Izd-vo AN SSSR, 1939.- 463s. In Russian

2. Gerschon MD. The second Brain. New York, 1998.- 179pp.

3. Sotnikov OS. Ob"edinennaya neyronno-retikulyarnaya teoriya. S-Pb: Nauka, 2019.- 239s. In Russian

4. Lavrent'ev BI. Morfologiya antagonisticheskoy innervatsii v avtonomnoy nervnoy sisteme i metody ee issledovaniya/ V kn.: Morfologiya nervnoy sistemy. M.: Medgiz, 1946.- S. 13–83. In Russian

5. Lengley Dzh. Avtonomnaya nervnaya sistema. Chast' pervaya. M.-L.: Gos. Izd-vo, 1925.- S. 1-70. In Russian

6. Khaulike I. Vegetativnaya nervnaya sistema. Bukharest: Med. Izd-vo, 1978.- 350s. In Russian

7. Lawrentiew BI. Experimentell – morphological Studien uber den feineren Bau des autonomen Nervensystems. I. Die Beteiligung des Vagus an der Herzinnervation. Ztschr. microsk. anat. Forsch. 1929;16(3– 4):383–411. In German

8. Sokovnin NM. Materialy dlya fiziologii aktov vyvedeniya i zaderzhanii mochi (Iz Fiziologicheskoy laboratorii Kazanskogo universiteta). Kazan': Tipografiya Universiteta, 1877.- 43s. In Russian

9. Solov'eva IA. Razvitie afferentnoy innervatsii pishchevoda tsyplyat. Arkh. anat. 1965;9:64–70. In Russian

10. Milokhin AA. Chuvstvitel'naya innervatsiya vegetativnykh neyronov. L.: Nauka, 1967.- 67s. In Russian

11. Sotnikov OS, Markov II. Kontseptsiya retikulyarnoy organizatsii nervnoy tkani Aleksandra Dogelya. Morfologicheskie vedomosti. 2018;1:8–9. DOI: 10.20340/mv-mn.18(26).01.8-19. In Russian

12. Ramon y Cajal S. Degeneration and Regeneration of the Nervous System. N-Y: Hafner publishing Co, 1959.- 123pp.

13. Ramon y Cajal S. Neuron Theory or Reticular Theory? Objective Evidence of the Anatomical Unity of Nerve Cells. Madrid: Consejo Superior de Investigaciones Cientificas. Instituto Ramon y Cajal, 1954.- 275pp.

14. Sotnikov OS. Dvuyadernye i mnogoyadernye neyrony obrazuyutsya sliyaniem. Kletochnye tekhnologii v biologii i meditsine. 2021;2:79-84. DOI: 10.47056/1814-3490-2021-2-79-84. In Russian

15. Golgi C. The neuron doctrine – theory and facts. Nobel Lecture. 1906. Nobel lectures, Physiology or Medicine. 1901–1921. Amsterdam: Elsevier Publ. Comp., 1967.- P. 189–217.

16. Romeys B. Mikroskopicheskaya tekhnika. Per. s nem., pod red. I.I. Sokolova. M.: Izd-vo inostrannoy literatury, 1953.- 719s. In Russian

17. Markov II, Petrova ES, Markova VI. Universal'ny metod elektivnogo vyyavleniya argirofil'nykh struktur. Morfologicheskie vedomosti. 2016;1:114–117. In Russian

18.

19.