[Cytoarchitectonic and neurochemical properties of spinal cord in teleost fishes].

Traditional neuromorphological and NADPH-diaphorase methods were used to study the topography, morphology and neurochemical organization properties of spinal cord in teleosts fishes. The heterogeneous population of NO-producing motoneurons was revealed in the motor column of spinal cords from studied species. Dendrites of primary motoneurons formed rich plexus at the spinal segment periphery. This morphological pattern is determined by translational motion of the fishes in the water (trunk-tail movement), and has no connection with the origin of upper and lower extremities. The NO-producing capacity of spinal motoneurons shows their connection with premotor NO-ergic brain system, including over situated motor centers of reticular formation and descending projections of giant steam neurons (Mauthner and Muller cells). The NO-producing Rohon-Berd neurons were found in the dorso-medial part of spinal cord from studied fishes. These cells with the ascending propriospinal targets form spinal nociceptive system. Thus, the sense Rohon-Berd cells and most motor neurons of studied bony fishes are nitric oxide synthesizing ones. Spinal cord NO-synthesizing territories are situated in concordance with dorso-ventral histochemical gradient. Spinal cord interneurons of these fishes produce nitric oxide selectively. The quantity of NO-synthesizing reticular cells is determined by two main factors: the connection with the specialized neurochemical complexes, where NO is a specific neuromodulator, and individual properties of spinal cord structure directed by conditions of morphoadaptation.

[Seasonal characteristics of gametogenesis in the Corbicula japonica].

A morphological study of gonads in Corbicula japonica made it possible to distinguish between five stages of gonad maturity. It has been established that stages of active gametogenesis, prespawning and of spawning go almost in parallel and in the shortest time. In July, with the beginning of spawning, gametogenesis does not stop, and oogenesis proceeds up to the end of August. Dynamics of changes of some chemical substances in oocytes was followed. High concentrations of, respectively, RNA, albumens, lipids, glycoproteins and proteoglycans were revealed in oocyte nuclei and nucleoli both at the beginning of the development, and at the stage of active gametogenesis. This testifies in favor of a synthetic activity of these cells.

[Neurosecretory activity and the dynamics of the lipid content in the CNS neurons in the bivalve mollusk, Gray's mussel (Crenomytilus grayanus Dunker)]. / Nerosekretornaia aktivnost' i dinamika soderzhaniia lipidov v neironakh TsNS dvustvorchatogo molliuska--midii Greia.

Neurosecretory process was studied in the aspect of lipid exchange in the CNS ganglia in the bivalve mollusk using light optics, electron microscopy, cytological and biochemical methods. Neurosecretory material forming was shown to be followed by changes in volume in neuron, nucleus and nucleolus, increase of nucleolar-plasmic relations, granular endoplasmic reticulum proliferation of mitochondria and complex dictyosomes. Changes in lipid content are inversely proportional to the neurosecreted amount in the neuron. The more active secretory process is, the smaller grows the number of lipid-containing cells, common lipids phospholipids. It is concluded that lipids structurally and energetically maintain the neurosecretory material synthesis.