[Specific molecular and morphological changes in cardiomyocytes of hibernating ground squirrels in different periods of annual cycle].

Structural and molecular changes in cardiomyocytes of hibernating ground squirrels in different periods of the annual cycle were analyzed by means of electron microscopy and polymerase chain reaction. Morphological analysis showed an increase in relative area of sarcoplasmic reticulum in cardiac muscle of ground squirrels preparing to torpor compared to active summer animals. The size of sarcoplasmic reticulum in cardiomyocytes of torpid animals was reliably less than in any other condition of ground squirrels in the annual cycle. The results of molecular analysis showed the decrease in sarcoplasmic reticulum Ca(2+)-ATPase gene (SERCA2a) expression .at all stages of hibernation process and also in periods of autumn activity compared to control mRNA level in active summer animals. The revealed season changes in structure of sarcoplasmic reticulum and sarcoplasmic reticulum Ca(2+)-ATPase gene expression are discussed in regard to adaptation of ground squirrels to hibernation.

[Distribution of proteins inside polyelectrolyte microcapsules depend on pH of medium].

Distribution of bovine serum albumin and ferritin inside polyelectrolyte microcapsules was studied by transmission electron and confocal microscopy at the pH range 2-5. It was estimate that protein's distribution depends on isoelectric point (pI) and first polyelectrolyte used for preparation of capsule shell. So peptide is placed in the bulk of capsule if pH values of medium are lower isoelectric point of protein and polycation was used as a first polyelectrolyte layer. If the first polyelectrolyte was polyanion, the protein is located near internal surface of the shell. The protein is situated near internal surface of the shell for both polyelectrolytes when pH is equal to pI.

[The strategy of the "useful sun" improves physical endurance and structural adaptation in the myocardium].

The action of solar light transformed by special screens has been studied on CD-1 male mice. In the active control group, mice were irradiated through screens absorbing the UV-component. In the experimental group, screens transforming the UV-component into the orange-red light were used. In the active control, changes in the swimming activity, as compared to the same parameter before irradiation, were manifested much less than in animals of the experimental group. A morphological analysis showed changes in the structure of all cardiomyocyte organelles studied: the relative area of mitochondria in the experimental mice increased by more than 20% compared to intact animals (p < 0.05). A significant increase in the area of the sarcoplasmic reticulum, by 23.4% (p < 0.05), and in the volume of the myofibrillar apparatus, by 19.4% (p < 0.05), was detected. The results of our experiment show that the irradiation with using an additional orange-red component improves the physical endurance 1.5 times and initiates morphogenetic processes in cardiac muscle cells.

[Photon radiation-induced structural and functional changes in the myocardium of hypertensive SHR rats].

Male rats were irradiated by a Korobkov photon light-emitting diode matrix with a maximum irradiation at 612 nm every day 1 h per day for 13 days. After a course of irradiation, the rhythmoinotropic characteristics of the cardiac muscle significantly improved. Exposure to photon radiation initiated an active rearrangement in myocytes as shown by a morphological analysis. Considerable changes were found in the structure of sarcoplasmic reticulum (SR); the area of SR profiles increased more than twofold compared to control. This suggests a proportional increase in the ability of SR to absorb calcium, due to both an increase in its buffer capacity and possibly, an improved functioning of Ca2+ ATPase of the reticulum. Probably, the photon therapy leads to the normalization of calcium homeostasis in myocytes and improvement of the characteristics of the cardiac muscle contraction-relaxation cycle. Furthermore, changes in the proportions of the myocardium capillaries (increased by 75% compared to control; p < 0.001) and the area of mitochondrial profiles of myocytes (increased by 13%; p < 0.05) were observed, which lead to more active metabolic processes and a rise in energy potential in myocardial cells after photon radiation treatment.

Experimental testing of the role of cytoskeleton in the solution by neurons of problems facing the brain.

Investigation of the influence of cAMP on neuronal electric activity suggests that nerve cells can solve problems using an intraneuronal calculating medium based on the cytoskeleton. When a new problem is posed, this structure has to be disassembled and assembled by the neuronal molecular computer according to the program recorded in DNA. If DNA lacks an appropriate program, the cytoskeleton will not be assembled. In our experiments, fishes which were rotated simultaneously around two mutually perpendicular axes lost their swimming ability, and some dramatic changes were observed in the cytoskeleton of their Mauthner neurons. These changes disappeared after a long-term rest: the cytoskeleton was restored simultaneously with the ability for normal swimming.

[Morpho-functional changes of Mauthner neurons after treatment with neuropeptide kyotorphin ]. / Morfofunktsional'nye izmeneniia mautnerovskikh neironov pri vozdeistvii neiropeptida kiotorfina.

Influence of neuropeptide kyotorphin (L-thyrosyl-L-arginine) treatment on goldfish Mauthner cells was studied separately or in combination with prolonged natural stimulation of these neurons. The neuroprotective effect of this substance at both functional and ultrastructural levels was demonstrated. Possible mechanisms of kyotorphin action is discussed with regard to its modulating effect on intracellular calcium ion concentration.

[Ultrastructural localization of calcium pyroantimonate in Mauthner neurons of goldfish fry adapted to natural stimulation]. / Ul'trastrukturnaia lokalizatsiia piroantimonata kal'tsiia v mautnerovskikh neironakh mal'kov zolotoi rybki, adaptirovannykh k estestvennoi stimuliatsii.

The localization of Ca2+ in control and adapted goldfish fry Mauthner cells (M-cells) revealed by sedimentation with potassium pyroantimonate technique was investigated. It has been shown the following. 1. In the control M-cells electron dense precipitates are present in the extracellular space, commonly within the active zone clefts of chemical synapses, throughout the whole apposition of the mixed synapses and in the synaptoplasm of both type afferent boutons. No precipitates were seen in the cytoplasm of M-cells. 2. After long term natural (vestibular) stimulation (LTNS), resulting in a strong functional suppression of M-cells, precipitates disappeared entirely from active zones but remained numerous in the cytoplasm of M-cells. The distribution of precipitates within the cytoplasm was non-uniform, the highest density was observed on the surfaces of intracellular organelles and elements of the cytoskeleton. 3. In fatigued M-cells after LTNS and after a subsequent one day rest the distribution of precipitates was less intensive, while in the whole it resembled that of fatigued M-cells. 4. In adapted M-cells the distribution of precipitates was similar to that observed in control. M-cells after LTNS, but the amount and size of the precipitated grains were noticeably increased. 5. The most numerous precipitates were seen in adapted M-cells after LTNS. They were localized throughout the postsynaptic cytoplasm and in a lesser order in the presynaptic cytoplasm. 6. After one day rehabilitation the intensitivity of cytochemical reaction of Ca2+ ion precipitation restored to the initial stage characteristic of adapted M-cells before LTVS. The results obtained suggest that the total concentration of Ca2+ ions in adapted M-cells and the dynamics of their exchanges between cytosole and intracellular depots, such as the smooth endoplasmic reticulum, may increase to keep a normal or even increased functional activity of M-cells, both before and after the LTNS.

Effects of L-thyrosyl - L-arginine (kyotorphin) on the behavior of rats and goldfish.

The effects of kyotorphin (KTP), a dipeptide (L-Tyr-L-Arg), on the level of sensory attention to stimuli of different modalities in rats and the exploratory behavior in goldfish were investigated. In both cases KTP was found to suppress the exploratory activity. When 5-HTP, a precursor of serotonin synthesis, is activated the inhibitory effects of KTP increased. It is assumed that the regulatory effect of KTP on the exploratory behavior of animals is mediated by the monoaminergic (neurotransmitting) brain systems, as distinct from its analgetic effects, which are mediated by the opioid brain systems.

[Features of morphofunctional rehabilitation of Mauthner neurons after fatigue]. / Osobennosti morfofunktsional'noi reabilitatsii mautnerovskikh neironov posle utomleniia.

Structural reorganization of smooth endoplasmic reticulum (SER) in relation to changes in functional state of neurons has been investigated using fatigue and subsequent rhabilitation of the goldfish Mauthner (M-) cells as experimental approach. The recovery of original structure of SER in distal parts of dendrities after its significant proliferation, caused by a 3 h natural stimulation, markedly retarded, as compared with quickly normalized functional activity of M-cells. At the same time in somata and proximal parts of dendrites the structural recovery of SER coincided with restoration of the initial function of M-cells. The results suggest that within a single neuron SER with its obvious structural plastisity the neuron functional activoty is supported and restored through regulating the extent of proliferation angmenting Ca(2+)-accumulation in its compartments. Nevertheless SER posseses certain autonomy in structural recovery within somata and dendrites. Such differences of SER plasticity in different parts of the same neuron presumable reflect differences in interaction of its individual compartments with the cytoskeleton and adjacent cytoplasm, or may be caused by different activity of synapses situated on the soma and dendrites.

Smooth endoplasmic reticulum in fish Mauthner cells at different functional states.

The ultrastructure of Mauthner cells of goldfish fry and adult xenotoca in intact state and after prolonged natural stimulation has been studied qualitatively and quantitatively. Additionally, Mauthner cells of intact adult goldfish and adult rotan Percottus glehni were investigated. In all adult fish the dendroplasm of the two major dendrites was shown to contain a regular network of smooth endoplasmic reticulum, with cisterns and tubules arranged transversally to the dendrite stem. In the Mauthner cells of intact goldfish fry, the reticulum was not clearly expressed, the transversal cisterns occurred occasionally. After stimulation, however, it became more developed probably due to proliferation of additional transversal cisterns. The periodicity of transversally oriented cisterns in the dendrites of Mauthner cells in each fish species studied was nearly the same. However, the number of transversal cisterns per unit of dendrite length, and the total length of cisterns and tubules per unit of cross-section area varied both within and among the species. These parameters increased after stimulation. It is suggested that the proliferation of the transversal cisterns in the endoplasmic reticulum and the extent of their development depend on the functional state of the afferent synapses and the plasticity of the smooth reticulum reflects the involvement of postsynaptic mechanisms in regulation of Mauthner cell stability presumably via the regulation of calcium homeostasis under varying conditions of functioning.

[Changes in the ratio of granular and agranular endoplasmic reticulum of the Mauthner neurons in fishes as an index of the compensatory processes during sensory stimulation]. / Izmenenie sootnosheniia granuliarnoi i agranuliarnoi éndoplazmaticheskoi seti mautnerovskikh neironov ryb kak pokazatel' kompensatornykh protsessov pri sensornoi stimuliatsii.

Endoplasmic reticulum structure was studied on Mauthner neurons of adult fish and fry. Two-fold decrease of extension of rough endoplasmic reticulum components and similar increase of extension of smooth endoplasmic reticulum components were found to occur following long-term stimulation of Mauthner neurons. The significance of transformation of rough endoplasmic reticulum into smooth one as a result of neuronal compensatory response was discussed.

[The reaction of the cytoskeleton and smooth endoplasmic reticulum of Mauthner's neurons in goldfish to partial denervation and prolonged sensory stimulation]. / Reaktsiia tsitoskeleta i gladkoi éndoplazmaticheskoi seti mautnerovskikh neironov zolotykh rybok na chastichnuiu denervatsiiu i dlitel'nuiu sensornuiu stimuliatsiiu.

Structure of smooth endoplasmic reticulum and cytoskeleton of goldfish Mauthner neurons were studied together with the behavior of fish after partial deafferentation of one of the dendrites with following long-term natural stimulation of another one and soma. Strong disturbance of cytoskeleton and proliferation of smooth endoplasmic reticulum especially of its transversely localised component accompanies exhaustion of Mauthner neurons caused by stimulation in normal absolute afferentation. On behavioral level it is manifests in significant suppression of fish motor activity. Similar stimulation of partly deafferentated Mauthner neurons turns to be more sparing both for fish behaviour and Mauthner neurons structure. Proliferation of endoplasmic reticulum was not in fact observed and in the cytoskeleton bundles of filaments were detected which implies improvement of its physico-chemical characteristics and increase of resistance to external factors. Probably, this relative resistance of partly deafferentated Mauthner neurons of fish to long-term natural stimulation is conditioned predominantly by postsynaptic mechanisms and is likely linked with reorganization in cytoskeleton, caused by preliminary change of Mauthner neurons innervation.