Ultrastructure of nodose ganglia of the vagus nerve in burns

Ultrastructural changes of neurons of vagus nodal ganglia on section material of 30 dead persons in different periods of burn disease aged from 14 to 75 have been studied. Examination of the state of the nodal ganglia in different periods of burn disease showed ultrastructural changes in neurons, glial cells, blood capillary endotheliocytes, mitochondria, endoplasmatic net nuclei and cell membranes. The most marked destructive changes were seen in patients who died in late term of burn disease.     

Changes in the brain neurons of the recipient around an embryonic nerve tissue transplant

Ultrastructure of adult neurons (sensomotor cortex) of recipient brain tissue localized in the vicinity of developing embryonic nervous tissue transplant has been studied. Partial dedifferentiation of pyramidal neurons has been revealed four days after the transplantation. The following changes were observed: dispersion and nearly complete absence of granular endoplasmic reticulum: appearance of a multitude of small mitochondria and disappearance of large ones; the presence of a large number of free polysomes; marked clearing of nuclei, and the presence of large nucleoli. No destructive processes in neurons were observed.     

Quantitative morphological characteristics of developing neurons after partial deafferentation of the sensory trigeminal nuclei

We have studied different types of neurons in the sensory trigeminal nuclei stained by the Golgi method in kittens aged 30 days with bilateral transection of the lingual nerve, made on the fifth postnatal day. We have shown that deprivation of afferent inflow from the tongue to trigeminal neurons leads to changes in the structure of all types of cells: reticular, arborescent, and bushy (68, 61, and 46% neurons respectively had changed), short-dendrite cells having changed to a lesser extent (16% changed neurons). The multipolar giant neurons hardly changed. The structural changes involved changes in the size of the bodies, number, length, and ramification of dendrites, and changes in their orientation and pattern of ramification, compared to the normal. We observed destructive changes resulting in a decrease in the quantitative parameters, and constructive changes resulting in an increase in the latter. Reticular and arborescent neurons showed both destructive and constructive changes, the short-dendritic neurons mainly constructive changes, and bushy neurons mainly destructive changes. The analysis of the differently directed rearrangements of the dendrite geometry in different types of deafferentated trigeminal neurons allowed us to put forward some proposals concerning the different functional role of these groups of cells in the system of afferent impulsation entering via the lingual nerve.Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR. Institute of the Brain of the All-Union Research Center of Mental Health, Academy of Medical Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 17, No. 4, pp. 522–530, July–August, 1985.     

The ultrastructural reorganization of the neurons in some brain formations during the deprivation of paradoxical sleep]

Electron microscopy was used to study intracellular changes in the dorsal hippocampus, lateral hypothalamic nucleus and pontine reticular formation of rats after 96-hour paradoxical sleep deprivation. It was found that compensative-accommodative processes predominate in the majority of neurons. At the same time destructive changes are detected in some cells. In changed neurons the ultrastructural signs of damage to protein-synthesizing apparatus were observed. These changes can be as a result of disturbances of protein biosynthesis.     

Ultrastructure of the cerebral cortex and hippocampus of rats in the early postresuscitation period following total ischemia

The rat frontal brain cortex and CAr hippocampal region were studied on the 4th day after 10-min complete ischemia. It has been established that the number of "dark" osmiophilic neurons was increased. The reparative, destructive and adaptive processes in cells were observed. The most prominent destructive changes were found in CAr hippocampal region, they can be associated with the microcirculatory disturbances. The hypertrophic thread-like mitochondria appear in the nervous and glial cells, with the quantity of lipofuscin granules increasing. Lipofuscin and hypertrophic mitochondria are thought to provide energy exchange in the brain cells during the postischemic period, forming one of the mechanisms of intracellular adaptation to hypoxia.     

Effect of gamma-radiation of an extremely high dose on the cerebral cortex of the rat (ultrastructural aspects)

For 24 h after total gamma-radiation of mature Wistar male rats (180-210 g) in the dose of 150 Gy, ultrastructural rearrangements of the cerebral sensomotor cortex are presented as small destructive changes in neurons, neuroglia and vascular endothelium. Total combination of the changes in ultrastructure of the blood capillaries and perivascular astrocytes makes it possible to suppose that permeability of the microvascular bed wall is increased. At this period, together with the destructive changes there are evidently certain compensatory-restorative processes, developing in the cerebral tissue. It is possible to suppose that already during the first hours after the radiation the ultrastructural changes of neurons are resulted not only from the direct effect of radiation, but from certain influences of the radiation damage of neuroglia and microvessels.     

Quantitative evaluation of the cytoarchitectonic reorganization of the locus coeruleus in the brain stem under the influence of 6-hydroxydopamine

It has been demonstrated the reorganization of structure of locus coeruleus in the animals treated intracisternally with 300 micrograms of 6-hydroxydopamine (6-OHDA) which selectively causes the lesion in catecholaminergic system using the method of quantitative estimation of the degree of uniformity and isotropy of structures. After administration of specific neurotoxin in early stages chromatolytic changes were observed in neurons which were not yet destructive but contractive for long. After injection of 6-OHDA in 36 days in the cytoarchitectonic structure were observed marked changes in uniformity and isotropy of neuron distribution within some groups in locus coeruleus versus controls.     

Effect of chronic alcoholic intoxication in the rat on the structural organization of the caudate nucleus in their progeny

By means of light (Nissl and Golgi), electron microscopy, as well as using morphometry, structure of neurons and interneuronal connections of the nucleus caudatus has been studied in 21-day-old rats reproduced by chronically alcoholized parents. As demonstrated the investigations, in young rats, physically underdeveloped, there are some signs of a delayed maturation in neurons, dendrites and synapses. Certain distrophic and reparative shifts are observed in all experimental animals. The distrophic changes of neural structures in the nucleus caudatus preponderate over the reparative ones, and in the destructive course not only the neuronal body is involved, but its processes, as well. The lesions of the latter influence organization of the synaptic contacts. This is demonstrated as a sharply decreased number of synapses of the formation studied in the field of vision. The occurring disturbance in the structure of dendrites, which play an important role in the primary integration of the information received by the neuron, can cause development of certain mental disorders in children born in alcoholic families. The reparative changes in neurons and interneuronal connections revealed suppose possible reversibility of the morphological changes observed in the offspring of drunkards.     

Ultrastructure of cells of the lateral field of the hypothalamus of the cat after exposure to electromagnetic radiation

Under the effect of electromagnetic radiation not any specific changes are revealed in the neural system unequivocally characterizing disturbances in its structure as a result of an excess absorption of electromagnetic energy. The ultrastructural changes revealed in the lateral fields of the cat hypothalamus are suitable for a well known scheme demonstrating the course of the pathological process, where three phases are distinguished: reactive, destructive and restorative. The pathological process develops gradually. The reactive changes in neurons and synapses, observed immediately after withdrawal of the electromagnetic action. increase during the following three months and result in coarse destructive disorders and in death of some neurons and synapses. In 6 months certain signs of restoration of the structures are observed. Under the effect of electromagnetic radiation water redistribution between the structures takes place, the sympathetic terminals loosing their fluid. Thus, certain conditions are produced for sticking together the synaptic vesicles. Possibly that deficiency of Ca++ ions contributes to it.     

Relation between the dynamics of early ultrastructural changes in the cerebral cortex of the rat and radiation dose

The electron microscopic investigation of the sensomotor zone in the cerebral cortex of mature male rats after total neutron and gamma radiation of high doses has demonstrated, that during first three hours after the influence the dynamics of ultrastructural changes in neurons, glial elements and microcirculatory bed depends on the radiation dose. After gamma radiation of 150 Gy, destructive changes in neurons, increased permiability of blood capillaries and development of perivascular edema are noted at earlier time than after radiation dose of 10 Gy. When the greater dose of radiation is used, also earlier reaction of the barrier structures in the brain is observed.     

RNA concentration in neuron-neuroglia systems of the retina and visual zones of the cerebral cortex during light deprivation and light stimulation]

A two-wave-length cytophotometry of the gallocyanin-chromium alum-stained preparations showed that in adult rats kept for 30 days in complete darkness there was a decrease in the RNA content in the perineuronal neuroglia of the retinal ganglion cell layer only, with no changes in the corresponding neurons. No changes were found in the neurons and in the perineuronal glia of the layer II---III of the visual cerebral cortex. After the end of light deprivation a 2-hour stimulation with a constant or flickering light did not influence the RNA content in the neurons of both regions of the visual analyzer studied, whereas in control rats this stimulation induced a marked increase in the RNA content in these neurons. Qualitative changes in the metabolism of the cellular RNA in the nervous system of adult animals under the effect of light deprivation are emphasized. Differences in the biochemical peculiarities of various neuron-neuroglia systems, depending on their localization in the visual analyzer, are discussed.     

The short-term and long-lasting changes in DNA and RNA synthesis in the cerebral cortex cells of animals subjected to hypoxia and nerve tissue transplantation]

The DNA and RNA synthesis in the cells of the brain cortex of intact rats and animals subjected to hypoxia, hypoxia with subsequent transplantation or by the local brain injury has been investigated. The DNA synthesis changes insignificantly in the case of hypoxia, it enhances slightly in the area of the injury and increases much more after transplantation. The RNA synthesis decreases considerably immediately after hypoxia and decreases much more 120 days later. Using the ultracentrifuge method it has been found that under the effect of hypoxia the number of nervous cells decreases, the number of glial cells does not change. The local injury in the nervous tissue enhances abruptly the synthesis in neurons and glial cells in the hypoxia-exposed animals, the embryonic nervous tissue transplantation normalizes the number of neurons in the specimens under study and the RNA synthesis in the neurons and glial cells.     

Changes in human cerebral cortex in various areas of concussion in severe cranio-cerebral injury

In 23 patients with a severe cranial-cerebral trauma the operative material (pieces of the cortex, obtained from the destructive, transitional and relatively preserved zones in the bruise foci with crushing, localized in various lobules of the cerebral hemispheres) has been studied. From 2 h up to 9 days after trauma, changes, characterizing the state of the vascular bed, nervous and glial cells have been followed. In the external area of the transitional zone in 15 patients and in the relatively preserved zone in all the patients reversibly altered nervous cells predominate. Only in the destructive zone in all 23 patients and in the whole transitional zone in 8 patients neurons in all cortical layers are deeply injured and unviable. Certain considerations on differential surgical tactics, when treating the bruise foci with crushing at a severe cranial and cerebral trauma are presented.     

Ultrastructure of neurons of the myenteric plexus in the normal cat and after temporary circulatory interruption

Ultrastructural organization of neurons in the myenteric plexus of the cat small intestine has been studied in norm and after the blood stream had been switched off for 4 hours and 1, 3, 7, 30 days after recirculation. Ultrastructural uniformity of perikaryons is noted, therefore it is impossible to reveal electron microscopically neurons with different functional qualities. Four morphological types of preterminal dilatations of axons are revealed. Some neurons demonstrate certain resistance to the four hours' ischemia of the intestine, predominance of reactive processes in most of the cells. Dynamics of destructive and reparative processes are followed in neurons and their processes after recirculation.     

Effect of hypokinesia on the ultrastructure of emotion-controlling structures in the rat brain

Hypokinesia lasting 40 and 90 days causes a number of ultramicroscopic reorganizations in neurons, synapses and glial elements of the singular cortex and the central amygdaloid nucleus. The longer the time of hypokinesia, the more numerous and variable the reorganizations become. For the amygdaloid body presence of neurons with various degree of chromatolysis, reactive and destructive changes of organells, agglutination and reduction in number of the synaptic vesicles, increasing number of synapses, possessing certain features of low functional activity are most specific. For the singular cortes are peculiar convolution of nuclear and cellular membranes, synaptic contact, increasing intercellular spaces, as well as changes in the structure of some axo-spine synapses, the spine apparatus including.     

Responses of neurons of intramural ganglia of the guinea pig pancreas to disruption of their connections with the CNS

Morphologic and morphometric investigation of the intramural nervous apparatus of the pancreas has been performed on guinea pigs, normal and after subdiaphragmal vagotomy in 7, 14 and 60 days. According to the morphologic state, the neurons are divided into 8 groups. Morphometry of the perikaryon and nuclei is carried out after Stefanov method. The confidence interval is estimated according to Strelkov tables. In the experimental animals, during the time of the investigation certain quantitative redistributions of the neurons according to their groups are revealed. On the 7th day amount of neurons with phenomena of swelling and chromatolysis, and in two weeks amount of atrophied cells increase. The size of the neurons, after their increase on the 7th day of the experiment, decreases on the 14th day. By this time size of the nuclei decreases, too. On the 60th day after vagotomy morphometric parameters approach those of the control animals. The data of the investigation make it possible to distinguish 3 phases in development of the morphofunctional changes in the neurons: changes connected with functional strain of cells (in 7 days), destructive changes (in 14 days), compensatory-restorative rearrangements (in 60 days). It is possible to conclude that dynamics of morphofunctional rearrangements of neurons under the conditions, when connection with the CNS is disturbed, obey general regularities of the neurodistrophic process in the organs at their disturbed innervation.     

Ultrastructure of the cerebral cortex in the rat after the effect of electromagnetic impulse

In mature rats an area on the head has been subjected to a single radiation for 1.5 sec with microwaves in the continuous regimen of generation, frequency 2.4 GHz level of the specific absorbed power 5 W/g, that is accompanied with appearance of convulsions. Under anesthesia specimens of the superficial layer of the cerebral superlateral part are taken and subjected to electron microscopical investigation. Immediately after radiation and in 2 h certain disorders in microcirculation and reactive changes of mitochondria in perikaryons, axons, dendrites, synapses of the neurons and in gliocytes are revealed. The mitochondrial changes are designated as "edematous". In 2 and 6 h in karyoplasm of some neurons membranous structures appear; they are interpreted as a result of heat denaturation of the nuclear proteins. In synapses, together with lesions of mitochondria, synaptic complexes undergo destruction and osmiophilic substance is accumulated in the subsynaptic zone along the whole length of the contact. In one day, essential destructive changes are revealed as severe lesions of some neurons, vacuolization and destruction of mitochondria, localized in all the structures. Pathogenesis of the neurological disturbances is based on disturbances of interneuronal interactions, connected with an immediate heat effect of the electromagnetic radiation on the structures responsible for the synaptic transmission and with a rapidly developing tissue hypoxia as a consequence of microcirculatory disturbance and a sharp inhibition of energetic metabolism.     

Effect of Ischemia on the Activity of DNA-Dependent RNA Polymerase and DNA Polymerase

Abstract: Ischemia, anoxia, and hypoxia of the brain have been shown to inhibit protein synthesis in the central nervous system. To obtain data on the changes in DNA-dependent RNA and DNA polymerases as they pertain specifically to neurons and glia, nuclear enriched neuronal and glial fractions were prepared, by sucrose-gradient centrifugation, from spinal cords of adult dogs that had been subjected to prolonged ischemia. The isolated fractions were assayed for enzyme activity by a radiochemical technique. RNA polymerase was affected more than DNA polymerase, activity being reduced considerably in both neurons and glia. Possible causes of the difference in sensitivity to ischemia are discussed.     

Cosinor analysis of the seasonal changes in the cytoplasmic RNA level in the neurons of preoptic nucleus in Rana temporaria L. under the ultrasound energy

Authors studied the effects of single, total doses of ultrasound energy (frequency: 24.6 kHz; intensity: 0.35 W/cm2) on the cytoplasmic RNA level in the neurons of preoptic nucleus (PON) in Rana temporaria L., in the annual cycle. The cosinor analysis revealed that the applied ultrasound energy caused significant changes in the cytoplasmic RNA content in the PON neurons in Rana temporaria L. in the annual cycle. This was expressed by an increase in rhythm amplitude, except for the females of the second experimental group. Simultaneously, the rhythm acrophase in the animals exposed to ultrasound energy was shifted to later months (i.e. to the hibernation period), as compared to the control animals, where the acrophase occurred in August in females and in September in males (i.e. in their active land life period). In the females of the first experimental group the ultrasounds induced a disappearance of rhythmic changes in the cytoplasmic RNA of the PON neurons in the annual cycle.     

Change in the concentration of nucleic acids and cAMP in neurogenic dystrophies of the stomach]

There proved to be a reduction of the RNA content in the tissue of the rat stomach in its dystrophic affection induced by traumatization of the duodenum, this pointing to the reconstruction of the cell genetic apparatus under conditions of extreme stimulation. Under the same experimental conditions there was a pronounced decrease of the cAMP level in the gastric mucosa of rabbits. The significance of the changes in the mechanism of the development of destructive and metabolic disturbances in the neurogenic dystrophic affections induced by extreme stimulation is discussed.