[Nitric oxide-ergic organization of medullar cranial nuclei in teleost fishes].

Traditional neuromorphological and NADPH-diaphorase methods were used to study and compare the topography and localization of medullar nuclei NO-ergic neurons in four teleost species: Pholis nebelosis, Hexagramus octogrammus, Carassius carassius and Pholidapus dybowskii. The peculiarity of medullar nuclei organization in teleost fishes consists in the weak topological disconnection of sensor and motor components with pronounced heteromorphism in their structure and the presence of subpopulations in their composition. In the fishes studied, NADPH-diaphorase was found in the trygeminal, octavo-lateral, facial, glossopharingeal and vagal nuclei. The number of NO-ergic neurons in the trygeminal nucleus was marginal and made up 9-14 % of the total cell number. About 40-60 % of NO-ergic cells were found in the octavo-lateral, facial, glossopharingeal and vagal nuclei.