[Morpho-functional changes in the frog urinary bladder receptors under the influence of barbiturates].

The effect of hexenal and nembutal on the tissue bushy receptors was studied the living isolated frog urinary bladder using methylene blue staining. These drugs were shown to induce the changes in the receptor pulse activity which included three phases: an initial sharp increase, an abrupt decline and a low protracted plateau. Reactions to hexenal and nembutal, while possessing some common features, had their own peculiarities.

Indicators of neuritis growth and retraction in tissue culture and histological specimens.

The dynamics of structural processes in cultured neurons was studied by time-lapse video recording and compared with the diversity of morphological structures in fixed preparations. Ellipsoid terminal structures indicate not the growth, but growth arrest of neurites and the start of their retraction (retraction bulbs). Only growth cones can be the indicators of neuritis growth and development.

Metal concentrations in Kandalaksha Bay, White Sea (Russia) following the spring snowmelt.

Elevated concentrations of dissolved and particulate Cd, Cu, Pb and Zn have been determined in the waters of Kandalaksha Bay (White Sea, Russia), following the ice melt in the spring of 2000. Dissolved metal maxima in the surface waters were observed at some stations and concentrations generally decreased with depth. The suspended particulate matter (SPM) comprised a non-lithogenic fraction in the range 12-83%, and had elevated metal concentrations that showed no trend with depth or salinity and was compositionally distinct from the sediments.

[Changes of functional-diagnostic indices during occlusive contacts reestablishment in the process of orthodontic treatment of patients with incisal disocclusion].

During orthodontic treatment of 42 patients with incisal disocclusions of different severity stages it was determined that during the period of occlusal contacts reestablishment a considerable increase of regional blood flow, a decrease of jaw bone density and an increase of masticatory muscles functional activity occurred. These changes were more pronounced in cases of deep incisal disocclusion than in cases with other types of incisal disocclusion.

Computerized morphometric analysis of the dendrites of Dogiel type II neurons.

Silver nitrate impregnation by the Bil'shovskii-Gros method was used to study the dendrites of Dogiel type II cells in the cat large intestine (local receptors) by computerized morphometric analysis. The following parameters were measured: the areas of the receptive field of the dendrite, the total area of all receptor elements, the total length of all branches of the receptor. There was significant individual variation in all these measures: the ratios of maximum to minimum values were 41, 29, and 45 respectively.

[Branched form of the encapsulated dermal receptors in rats].

Using electron microscope the receptors found in the zone of highest receptor sensitivity in the skin fold at the base of IV finger of rat hind limb were studied. These receptors are represented by complex incapsulated corpuscles consisting of a group of small endings similar to Pacinian corpuscles, which are densely packed and surrounded by a common connective tissue capsule. Each single primary receptor is provided with an unmyelinated receptor terminal, analogue of internal bulb, and a multilayered external bulb.

[Metallophilia in the Ranvier's nodes of nerve fibers in rats of different strains (histochemical study)].

Myelinated nerve fibers formed by the processes of LV spinal ganglion neurons were studied in two lines of rats selected according to high and low thresholds of nerve system excitability to electric current. Before ultrastructural study the fibres have been treated with potassium pyroantimonate. It was demonstrated that specific dense precipitate was deposited in the nodes of Ranvier of the nerve fibers of rats with low excitability thresholds; this precipitate was not found in the fibers of rats with high thresholds.

[Computer morphometric analysis of dendrites of the type II Dogiel neurons].

Dendrites of type II Dogiel neurons (the local receptors) stained with silver nitrate impregnation by Bilschovsky-Gross method, were analyzed with computer morphometry in cat large intestine. The following parameters have been measured: an area of dendritic receptor field, total area of all receptor elements and total length of all receptor branches. Significant individual variability was noted in the values of these parameters: the maximum value exceeded the minimum one by a factor of 41, 29 and 45, respectively.

[Morphological and functional changes of tissue receptors of an organ plexus under the effect of blockers of cytoskeleton assembly].

Colchicine and cytochalasine C exert modifying action on tissue receptors of urinary bladder of the frog. Under the effect of cytochalasine the period of vital staining of receptors were changed. Latent period of decoloration grew 37-56% longer while the period of staining accumulation grows 18% shorter.

[Ultrastructure of nerve endings of varying function in the wall of the frog urinary bladder].

Sensory and effector nerve endings were presented at ultrastructural level. Four morphological types of receptor terminals were identified that vary in peculiarities of neurilemma, organelle composition, matrix structure etc. These types were suggested to be ultrastructural equivalents for different functional states.

[The morphophysiological mechanisms in the adaptation of mechanoreceptors].

The review was dedicated to the analysis of mechanisms mediating mechanostimuli transformation into bioelectric process in sensory nerve endings Influence of viscous-elastic properties of nerve ending and of the surrounding tissues as well as neuromembrane ion channels on adaptive process in mechanoreceptors were examined in detail on the basis of recent research. Special attention was drawn to consideration of morphophysiological features of similarity and differences of various mechanoreceptor types (both free and non-free).

[The morphophysiological restructuring of the sensory bushy receptor of the frog bladder under the influence of colchicine].

Colchicine was shown to decrease the afferent spontaneous unit activity frequency as well as the number of small terminal receptor plates (< 5 mu) increasing, however, the number of large ones (10-25 mu) in frogs. Colchicine seems to act on neurolemma rather than on cytoplasmic microtubules.

[The local sensory neurons of the small intestine in the turtle (an intravital study)].

Morphological statics and dynamics of living sensory neurons and their dendrites were studied by means of automatic television image analyser in steppe turtle small intestine. Values of quantitative characteristics (squares of the terminal plaques and neuron body receptor zone, summary square of dendritic elements and specific density of the receptor innervations zone were obtained. Dynamics of terminal receptor plaques mechanical mobility was qualitatively characterized.

Morphological and electrophysiological peculiarities of sensory bush-like receptors of the frog urinary bladder.

Results of synchronous morpho-electrophysiological experiments conducted on living bush-like receptors of the urinary bladder of a frog (Rana temporaria) and results of their ultrastructural and cytochemical studies are presented in this article. It is demonstrated that these endings are mechanical receptors reacting to tactile stimuli. Rapidly and slowly adapting units are registered.

Brain neurite-stimulating protein promotes formation of mechanosensory endings in sensory neuron.

In the present study we have shown that in the organotypic culture of dorsal root ganglia (DRG) of 10-11 day-old chick embryos, the neurite-stimulating protein (NSP) from bovine brain promotes the development of branching mechanosensory endings. The light and electron microscopic observation revealed that the morphological features of these sensory endings are similar to those in vivo. A mechanical stimulation of these endings elicited bursts of impulses in the sensory neurons.

[The use of several types of metal cations--a new approach to the study of the metallophilia of Ranvier's nodes of nerve fibers].

Mechanisms of metal affinity of Ranvier's nodes of myelinated nerve fibers in the peripheral nerve system have been investigated. It is indicated that Fe(3+)-ions are able to reduce to Fe(2+)-ions. Ag(+)-ions compete with Fe(3+)-ions for places of adsorption in a gap [correction of chick] between myelinated segments of Ranvier's node.

[The autotomy process of the microcirculatory bed receptors].

Autotomy of receptors' endings in the intestine's microvascular bed was shown to entail a real breaking off of the end-plates or large fragments of receptors with their subsequent degeneration. The process of autotomy can be reproduced in the tissue culture. The TV-computer analysis revealed the autotomy both in developing structures in early ontogeny and in mature tissue receptors in adult animals.

[The structural dynamics of the afferent flow in the action on the receptor field of a low-intensity stimulant].

The pattern of changes in afferent flow from a uniform isolated receptor field (3-5 mechanoreceptor units) under the effect of unspecific external stimulus of low intensity, was studied. A diverse dynamics of the afferent flow was observed: the firing rate, relative distribution of discharges in time, the amplitude and the form of spikes, are altered. The changes occur simultaneously, as a rule, which renders the idea of afferent flow's structure rather uncertain.

[Autotomy of sensory nerve endings in the area of microvessels].

The phenomenon of autotomy of peripheral receptor terminals, in the area of the intestinal microvessel bed has been analysed. This phenomenon is accompanied with a real separation of the terminal patches or large fragments of receptors with their successive degeneration. The effect of the terminals autotomy is succeeded in reproducing and analysing in dynamics in tissue culture.

[Structural-functional and metabolic changes in the nervous system in low- and high-excitable rats deprived of paradoxical sleep].

Studying of the influence of 24-hour deprivation of paradoxical sleep phase (PSPh) on rats with different genetically determined levels of excitability of the nervous system allowed to establish: 1) significant changes in functional state of the central part of the nervous system responsible for elaboration and preservation of defensive conditioned reflexes; 2) considerable lowering of functional state of the peripheral nervous system expressed both in a decrease of tibial nerve excitability thresholds and in changing of morpho-tinctorial characteristics of the studied nerve receptor parameters. The degree of the observed effects of PSPh deprivation is dependent on animal line belonging.

[Myoneural contacts in the frog bladder wall].

Ultrastructural interrelations of myocytes with efferent axons have been studied in the wall of the frog urinary bladder. Structural peculiarities of axons making contacts and of those not making contacts with smooth myocytes have been revealed. Two forms of the myoaxonal contacts have been discovered: without axon plunging into cytoplasm of the myocyte and with plunging into it.