[Modulation of voltage-gated sodium channels by recombinant interferon-alpha2b in the human neuroblastoma cell line IMR-32]. / Moduliatsiia potentsiialupravliaemykh natrievykh kanalov kletok neiroblastomy cheloveka IMR-32 pri deistvii rekombinantnogo interferona-alfa2b.

Clonal human neuroblastoma cells imr-32 are a suitable model system for studies of neuronal excitability modulation. The ability interferon-alpha 2b "laferon" to modulate the mechanisms of electrical activity was studied in whole-cell patch-clamped undifferentiated human neuroblastoma cells IMR-32. It was shown that 1 h incubation of IMR-32 cells at 37 degrees C in medium with laferon (600 U/ml) exerted changes in voltage-dependent properties of Na(+)-channels. The results of the present study demonstrate that laferon decreased of Na(+)-channels sensitivity to changes of membrane potential leading of IMR-32 cells electrical excitability decrease.

[Structural changes induced by diethyl ether in cultured neuroblastoma cells]. / Strukturnye izmeneniia, vyzyvaaemye diétilovym éfirom v kul'tiviruemykh kletkakh neiroblastomy.

It has been found that neuroblastoma cells retract their neurites under the influence of ether in dose 1 ml in 15 ml of the cultural medium. Application of ether for two hours increases the ratio of the number of cells to the number of neurites from 9.94 +/- 2.12 in the initial state to 19.66 +/- 1.93 (P less than 0.002). An essential alteration of the cell shape and a decrease of their volume are observed as well. The reaction is typical of cells at different stages of morphological differentiation. The data obtained can be helpful for investigation of pharmacological preparations which prevent destruction of neurons under narcosis.

[Effect of intracellular administration of L-tyrosine and L-phenylalanine on voltage dependent calcium current in PC 12 pheochromocytoma cells]. / Vliianie vnutrikletochnogo vvedeniia L-tirozina i L-fenilalanina na potentsialozavisimyi kal'tsievyi tok v kletkakh feokhromotsitomy PC 12.

Changes in the high-threshold calcium current (Ica) induced by intracellular administration of L-tyrosine and L-phenylalanine have been studied on internally perfused PC 12 pheochromocytoma cells using whole-cell voltage-clamp technique. L-tyrosine (20 microM/l) not only prevented a decay of Ica occurring during intracellular perfusion but induced also its transient recovery. In contrast, L-phenylalanine (20 microM/l) accelerated a decline of Ica. Replacement of ATP in the perfusing solution by an equivalent amount of ADP (2 mmol/l) did not alter the effect of amino acids. alpha-methyl-D, L-tyrosine (a specific blocker of tyrosine hydroxylase) caused the effect similar to that of L-tyrosine.

[2 components of the high-threshold calcium current possessing different sensitivities to omega-conotoxin in the membrane of pheochromocytoma cells]. / Dva komponenta vysokoporogovogo kal'tsievogo toka, obladaiushchie raznoi chuvstvitel'nost'iu k omega-konotoksinu, v membrane kletok feokhromotsitomy.

Blockade of the high-threshold calcium currents by omega-conotoxin (CgTx) was investigated by patch-clamp recordings of whole-cell currents in cultured cells of pheochromocytoma PC12. CgTx (10 mumol/l) preferentially blocked only a steady-state component of the calcium current. Inactivated component was insensitive to CgTx (up to 50 mumol/l concentration). The two component nature of the high-threshold calcium current in pheochromocytoma PC12 cells was suggested.

[Changes in the morphometric parameters of neuroblastoma cells cultured at an elevated pH]. / Izmenenie morfometricheskikh parametrov kletok neiroblastomy, kul'tiviruemykh v usloviiakh povyshennogo pH.

The phenomena arising during morphological differentiation of neuroblastoma cells under pH of culture medium 8.0-8.2 have been investigated. The initial cell population divided into two parts--proliferating and differentiating cells--on the third day of cultivation in the modified medium. Reliable correlation between somatic size and neurite length has been found in differentiating cells. Thus somatic size may be used as morphological criterion of differentiated neuroblastoma cells under present conditions. The established relations may be used for the further investigation of morphofunctional alterations under induced differentiation of neuroblastoma cells.

[Evaluation of the distribution of lectin receptors on the surface of tumor and transformed cells using methods of variation statistics]. / Otsenka raspredeleniia lektinovykh retseptorov na poverkhnosti opukholevykh i transformirovannykh kletok s pomoshch'iu metodov variatsionnoi statistiki.

Statistical procedures were used to estimate lectin receptor distribution on the surface of ascite lymphoma cells, neuroblastoma C-1300 cells and of transformed human T- and B-derived lymphoid cell lines. Relationships between the arithmetic means and mean square variances for sample populations from each cell and ferritin- or colloidal gold-lectin combination were used to define four types of topographical distributions: uniform-ordered, uniform-random, random and clustered.

[Localization of lectin receptors on the surface of C1300 neuroblastoma cells]. / O lokalizatsii retseptorov lektinov na poverkhnosti kletok neiroblastomy C 1300.

D-mannose, D-galactose, N-acetyl-D-galactosamine, N-acetyl-D-glucosamine and L-fucose which are sugar determinants of receptors were found on the surface of neuroblastoma cells by means of four carbohydrate-specific lectin groups. Labeling of lectins was performed by horseradish peroxidase, ferritin and colloidal gold. Peculiarities of the lectin receptors distribution on the surface of immature neuroblastoma cells were detected.

[Surface charge of mouse neuroblastoma cells and changes during growth and morphologic differentiation of the cell population]. / Poverkhnostnyi zariad kletok neiroblastomy myshi i ego izmenenie v protsesse rosta i morfologicheskoi differentsirovki kletochnoi populiatsii.

Microelectrophoresis method was used to study the surface charge of murine neuroblastoma cells (clone C1300-N18TG2). It was shown that the surface charge of these cells was determined mainly by anionic groups of the membrane which were distributed with density 0.2 e/nm3 in the layer covering its outer surface. The thickness of this layer was about 10 nm. These groups interacted with Ca ions (binding constant Kca-10-50 l/mol) and were titrated according to pK-3.8. Trypsin, neuraminidase and N-bromosuccinimide (which irreversibly neutralize the carboxylic groups of proteins) decreased the electrophoretic mobility of neuroblastoma cells while tosylchloride (a specific reagent for aminogroups) slightly increased it. The surface charge depended also on the conditions of cultivation of cell population. Morphological cell differentiation induced by removing the serum from the culture medium increased their mobility by about 30%. During the cultivation of cells in a medium with 10 or 50% of serum variations of the their mean electrophoretic mobility value were observed which were opposite-phase to the value of the daily increment of the number of cells. It was assumed that these effects were connected with partial self-synchronization of cell population. It is concluded that the surface charge of the neuroblastoma cells determined by microelectrophoresis method is mainly determined by the carboxylic groups of membrane periphery proteins and gangliosides and the content of these membrane components depends on the stage of cell development.

[Calcium currents of differentiated mouse neuroblastoma cells]. / Kal'tsievye toki differentsirovannykh kletok neiroblastomy myshi.

Differentiated neuroblastoma cells (clone N18TG2-A1) were investigated by means of intracellular dialysis technique. A slow component of the potential-dependent inward current was observed in these cells. Changes in current amplitude produced by changes in the ionic composition of intra- and extracellular media showed that this component is carried by calcium ions. The calcium inward current was observed in all investigated cells. It could be activated by membrane depolarization to the level of -70 - -65 mV and reached maximum amplitude at -30 - -40 mV. Kinetic parameters of this current were studied. A conclusion is made that calcium current in differentiated neuroblastoma cells is similar to the fast component of the calcium current in normal neurons of rat dorsal root ganglion.

[Effect of changes in the pH of the medium on neuroblastoma cell differentiation in culture]. / Vliianie izmeneniia pH sredy na differentsirovku kletok neiroblastomy v kul'ture.

Morphological differentiation of neuroblastoma cells in culture was found to be depended on extracellular pH value. Increase of pH value up to 8.2 resulted in the appearance of both differentiated and dividing cell populations. The morphologically mature state of differentiated cells was observed at 7th-8th day and their population remained stable state for over 4 weeks. Increase of pH value to 8.5-8.9 caused retraction of cell processes of differentiated cells and inhibited multiplication of the dividing cells.

[Morphologic differentiation of neuroblastoma cells induced by dimethyl sulfoxide]. / Morfologicheskaia differentsirovka kletok neiroblastomy, indutsirovannaia dimetilsul'foksidom.

Morphological features of neuroblastoma cells cultured in the presence of 1.0% dimethyl sulfoxide (DMSO) were investigated. The induced differentiation was characterized by appearance of long axon-like processes (neurites), cell size enlargement and inhibition of cell growth. Quantitative criteria for cell differentiation depending on survival time in the modified medium were estimated. The increase of total length of neurites was linear with time, the rate of their extension being 20.0 +/- 3 micron/h. The area of differentiated cell soma is 6-7 times higher than that of control cells. Increase of the DMSO concentration to 2.0% did not intensify neurite growth and enlargement of cell size but suppressed mitosis. Morphological criteria of cell differentiation are compared with probable functional changes in these cells.

[Structural features of isolated and perfused neurons of Helix pomatia mollusks]. / Strukturnye osobennosti izolirovannykh i perfuzirovannykh neironov molliuskov Helix pomatia.

Ultrastructural features of the intact normal neurons of Helix pomatia L., were studied and compared with those of isolated and perfused neurons. The perfusion of the isolated neurons had no definite influence on the intracellular organelia membranes--endoplasmic reticulum, Golgi complex, the neurosecretary granules, pigment bodies. Some changes were manifested in the vacuolization of the structures, increase in the number of cytosomes and lysosomes, modification of the size and shape of the neurosecretory granules. No visible ultrastructural changes of the superficial membrane, submembrane parts of cytoplasm were observed after intracellular perfusion. The obtained data confirm the use of perfused neurons as a model for the investigation of electrophysiological properties of the somatic membrane.

[Ultrastructural characteristics of the dendrites of spinal neurons]. / Ul'trastrukturnye kharakteristiki dendritov spinal'nykh neironov.

Some kinds of dendritic protrusions were found in the different parts of the spinal cord grey matter connected with the long descending fibre systems. The small simple dendritic protrusions were localized in the medial part of the ventral horn. As a rule they were invaginated in the axon terminal which made the simultaneous synaptic contacts with them and with the basic trunk of dendrite. In the lateral parts of the V-VII laminae of the grey matter the dendritic branches were getting longer and more complex, the breaking forms and "crest" synapses appeared. There were some inclusions in the matrix which were probably the precursor of the spine apparatus and were called spine-like protrusions. Statistically authentic difference was determined between the size of the dendritic protrusions in the medial and lateral parts of the ventral horn grey matter.

[Types of organization of interneuronal contacts in the ventral horn of the cat spinal cord]. / Tipy organizatsii mezhneironnykh sviazei v ventral'nom roge spinnogo mozga koshki

The ultrastructure of intermediate neurons of the ventral horn of the spinal cord of cats was studied. It has been established that interneuronal contacts having different structural organization may be grouped according to the principle of different space distribution of pre- and postsynaptic elements. Contacts of the first type realize convergence of different synaptic effects on one post-synaptic structure. In contacts of the second type the synaptic action of the axon fibre or a terminal diverge to different elements of the neuropile. Several synaptic forms of contacts of the second type were revealed. The role of the above structures in the physiological activity of intermediate neurons of the spinal cord is discussed.

[The ultrastructure of portions of the cat spinal cord gray matter connected to fibers of different descending tracts]. / Osobennosti ul'trastruktury uchastkov serogo veshchestva spinnogo mozga koshki, sviazannykh s voloknami razlichnykh niskhodiashchikh traktov

Definite ultrastructural features were found in the regions of the cat spinal grey matter connected with different descending pathways, especially in the structure of dendritic membranes and relative quantities of axon terminals. Two types of destructive changes in myelinated axons and axon terminals in these regions were observed during experimental degeneration of descending fibres. Axon terminals of small size and F-type vesicles were subjected to degeneration after pyramidal tract lesion, while large terminals of both S-type and F-type were affected after sectioning of extrapyramidal tracts.