[Morphochemical study of alpha-synuclein, iron and iron-containing proteins in the substantia nigra of the brain in Parkinson's disease]

OBJECTIVE

To study, using a complex morphochemical approach, the localization of alpha-synuclein, iron compounds and iron-containing proteins in the structures of the substantia nigra of the brain in Parkinson's disease (PD).

MATERIAL AND METHODS

Histochemistry and immunohistochemistry methods have been used to study the localization of pathological alpha-synuclein (α-Syn-p129), iron compounds and iron-containing proteins - transferrin receptor and ferritin in neurons and neuroglia in the substantia nigra of the brain of deceased PD patients and persons with no neurological symptoms detected during life (control).

RESULTS

In the substantia nigra of PD patients, in comparison with the control, a stable accumulation of pathological alpha-synuclein (α-Syn-p129) in the bodies and processes of neurons was found, and in the neuroglia and neuropil - the accumulation of iron (II) and ferritin heavy chain, the reaction of microglia to protein CD68 was moderately elevated. The transmembrane protein CD71 was detected equally in the brains of PD patients and in controls.

CONCLUSION

Synaptic protein alpha-synuclein in PD turns into a pathological metabolite that accumulates in the structures of substantia nigra, and probably disrupts the conduction of nervous excitation. Excessive accumulation of the ferritin heavy chain in neuroglia can increase the concentration of reactive forms of iron and increase neurotoxicity. The uniform distribution of the transmembrane glycoprotein CD71 in the of substantia nigra structures both in the control and in PD patients indicates the preservation of non-heme iron transport during the neurodegenerative process.

[The role of mercury and arsenic in the etiology and pathogenesis of Parkinson's and Alzheimer's diseases]

A critical review of literature data on the toxic effects of mercury and arsenic on the human brain and their relationship with the etiology and pathogenesis of neurodegenerative diseases such as Parkinson's and Alzheimer's diseases is presented. In the first case, the toxic effect of mercury and arsenic on the brain stimulates oxidative stress, which leads to the formation of free oxygen species and a decrease in the antioxidant defense of neurons. In the second case, the harmful effect of mercury changes the structure and properties of β-amyloid, and the toxic effect of arsenic contributes to its accumulation. In the pathogenesis of the diseases under consideration, particular importance is attached to the reaction of astrocytes that initiate neuroinflammation, which is also characteristic of mercury and arsenic intoxication. Considering that the symptoms recorded during intoxication with mercury and arsenic are in many respects similar to those of Parkinson's and Alzheimer's diseases, and their pathogenetic mechanisms (oxidative stress and neuroinflammation) coincide, then the toxic effects of mercury and arsenic in neurodegenerative diseases analyzed in this review can be characterized as the influence of the most significant risk factors.

[The role of aluminum and lead in the development of Alzheimer's and Parkinson's diseases]

The article summarizes the data available in the literature on the toxic effects of aluminum and lead on the human brain and assesses the relationship of these effects to the etiopathogenesis of the most common neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. The accumulation of ions of these metals in the brain structures leads to chronic intoxication that is manifested by the morphological signs that are typical for Alzheimer's disease, such as deposits of β-amyloid and τ-protein mainly in the frontal and temporal regions of the cortex, and for Parkinson's disease, such as degeneration of dopamine neurons in the substantia nigra and their accumulation of α-synuclein. The most likely forms of participation of aluminum and lead ions in the mechanisms of neurodegeneration are the replacement of bivalent metal ions necessary for brain functioning, oxidative stress initiation, epigenetic modifications of histones, and increased expression of noncoding ribonucleic acids.

[Clinical and morphological analysis of a caseof Parkinson's disease]

Parkinson's disease (PD) is a neurodegenerative disease that belongs to a group of cerebral proteinopathies. The main pathomorphological signs of PD are neuronal degeneration in the midbrain substantia nigra and detection of pathological forms of the synaptic protein α-synuclein in the nigral neurons. At the same time, the pathological forms of α-synuclein in this disease have been recently shown to accumulate in the cells of not only the central, but also peripheral autonomic nervous system. The paper provides a clinical and morphological description of a PD case in a 70-year-old patient, which demonstrates that there are typical α-synuclein-positive inclusions in the brain regions (substantia nigra, caudate nucleus, and frontal cortex), salivary glands and colon. The systemic nature of α-synucleinopathy in PD is important in both clarifying the pathogenesis of the disease and elaborating new approaches to its diagnosis and, in the future, to targeted therapy.

[Morphochemical changes in human striatum during aging.]

Age-related neurodegenerative diseases, including Parkinson's disease, are characterized by a number of pathomorphological signs, such as neuron loss in certain brain structures, gliosis, iron accumulation. However, the literature indicates that these signs can also be observed during normal (physiological) aging. The aim of our work was to evaluate qualitative and quantitative morphochemical changes in neurons and neuroglia, and also to localize iron (II) compounds in the human striatum during physiological aging. In the old age group, compared with the mature one, the size of the neuron bodies was significantly smaller, the neuronal distribution density did not differ, but the distribution density of both the overall glia and astrocytes was significantly higher. In the old age group, the accumulation of iron (II) compounds were seen along the walls of the vessels, as well as inside the cytoplasm of neurons and glial cells. We conclude that the results obtained may serve as a basis for the comparative study of the neurodegenerative process and for the earlier and more accurate diagnosis of neurodegenerative diseases associated with aging, including Parkinson's disease.

[Lewy bodies in Parkinson's disease: histological, immunohistochemical, and interferometric examinations]

OBJECTIVE

To quantify the morphochemical characteristics of Lewy bodies detected in the substantia nigra in patients with Parkinson's disease (PD).

MATERIAL AND METHODS

The investigators studied the localization of alpha-synuclein (α-Syn) and the distribution of neurofilament protein and synaptophysin by immunohistochemical assas and compared with the results of interferometry and computer-assisted morphometry of Lewy bodies in the autopsy specimens of the substantia nigra from PD patients.

RESULTS

Three groups of synuclein-positive aggregates differing in shape were identified. Mature Lewy bodies had a rounded shape, a concentric structure, a poorly stained core, and, as compared with neuropil, a high phase difference value. Comparison of the localization of α-Syn, neurofilaments, and synaptophysin showed that immunostaining of neurofilaments in the peripheral layer of Lewy bodies was shifted closer to the nucleus and the localization of synaptophysin and α-Syn coincided.

CONCLUSION

Synuclein-positive protein aggregates showed heterogeneity in structure, shape, and protein composition in PD. The localization of neurofilament protein and synaptophysin in Lewy bodies attests that the cytoskeleton and neuronal synaptic vesicle trafficking in the substantia nigra are impaired in BP.

[Neurochemical and morphological changes of microstructures of the compact part of the substantia nigra of human brain in aging and Parkinson's disease (literature review).]

For investigation of pathogenetic patterns of Parkinson's disease, it is important to adequately assess the mechanisms of age-related involution and morphological changes that are formed in the brain during this process. Clinical symptoms, detected in Parkinson's disease (rigidity, hypokinesia, tremor), indicate the involvement in the pathological process of nigrostriate brain formations due to the death of dopamine neurons in the compact part of the substantia nigra. At the same time, the loss of these neurons, as well as the change in the number of neuroglia cells in the substantia nigra of the brain, are detected not only in Parkinson's disease, but also in physiological aging. This review presents and compares data on the morphological changes in the compact part of the substantia nigra of the human brain in physiological aging and Parkinson's disease.

[Morphochemical changes in the substantia nigra cellular structures in Parkinson's disease]

AIM

to clarify the features of morphochemical changes in the substantia nigra cellular structures in Parkinson's disease.

MATERIAL AND METHODS

The structural characteristics of the substantia nigra were studied microscopically and quantified using computer morphometric methods at brain autopsies of individuals with Parkinson's disease who had died from intercurrent diseases and those who had no evidence of neurological disorders in their history (a control group).

RESULTS

This investigation could clarify the features of morphochemical changes in both the neural network structures and the glial populations of the substantia nigra in Parkinson's disease. The number of neurons containing tyrosine hydroxylase (a marker of dopamine neurons) in the compact part of the substantia nigra (a ventral region) was smaller and the density distribution of Lewy bodies was higher in the patients with Parkinson's disease than in the control group. The accumulation of iron (II) compounds in the cellular elements and neuropile and the increased expression of glial fibrillary acidic protein in Parkinson's disease were more pronounced than those in the controls.

CONCLUSION

Postmortem diagnosis in Parkinson's disease should be based on a full description of a set of neuronal and glial morphochemical and structural changes in the substantia nigra rather than on the identification of cellular markers for the neurodegenerative process.

[Morphological parameters of the heterogeneity of the substantia nigra in elderly men and women]

OBJECTIVE

to define the quantitative characteristics of cell structures in the substantia nigra pars compacta of neurologically healthy elderly people (men and women).

MATERIAL AND METHODS

Autopsy brain materials from neurologically healthy men and women who had died from intercurrent diseases at the age of 72 to 87 years were examined for quantitative characteristics of the substantia nigra pars compacta, by applying computed morphometric methods.

RESULTS

In the elderly people (men and women), the compactness of arrangement of neurons, including those containing tyrosine hydroxylase (a marker of dopamine neurons), was much higher and the glial index was lower in the ventral area of the substantia nigra pars compacta than in the dorsal area. Comparing the structures in the substantia nigra pars compacta showed that the neurons were larger in the dorsal area and the variability of the compactness of their arrangement and the glial index were higher in the women than in the men.

CONCLUSION

In the elderly people, the cell structures in the substantia nigra pars compacta are typified by high morphometric heterogeneity.

Quantitative morphochemical characterization of the neurons in substantia nigra of rat brain and its volume reconstruction

Three cell compartments differing by size and proportion of neurons were identified by 3D reconstruction of the substantia nigra pars compacta of the rat brain based on immunohistochemical localization of tyrosine hydroxylase, a marker of dopamine neurons. Dopaminepositive neurons prevailed over dopamine-free neurons (1.45:1) in the most voluminous (75%) dorsal part, and in smaller lateral and ventral parts, inverse cell ratios were observed: 0.54:1 and 0.78:1, respectively. Morphometry characterized the substantia nigra pars compacta as a structure consisting not only of several parts, but of horizons and showed differences between the neurons both in several parts and in several layers within the part. The revealed morphochemical heterogeneity of the substantia nigra pars compacta provides better understanding of the selective damage to its structures in Parkinson's disease.

[Morphological changes of neurons and neuroglial cells in the brain of senescence-accelerated prone 1 (SAMP1) mice]

Computerized morphometry was used to examine the sizes of neuronal bodies and the compactness of arrangement of neurons and neuroglial cells in layers III and V of the sensorimotor cortex in senescence-accelerated prone 1 (SAMP1) mice (an experimental group) and senescence-accelerated-resistant strain 1 (SAMR1) ones (a control group). In the SAMP1 mice as compared to the SAMR1 ones, the neuronal body sizes were significantly unchanged; the compactness of their arrangement decreased by 17 and 20% in layers III and V, respectively; that of neuroglial cells significantly increased by 14% in layer III only. In the SAMP1 mice versus the SAMR1 ones, the glial index rose by 36% in layer III and by 24% in layer V. During simulation of physiological aging, the sizes of neuronal bodies were shown to be virtually unchanged in the cerebral cortex; the compactness of their arrangement (cell counts) moderately reduced and that of neuroglial cells increased, which caused a rise in the glioneuronal index that was indicative of the enhanced supporting function of neuroglial cells during the physiological aging of brain structures.

[Changes in neuroglial interactions in the cerebral nigrostriatal structures in a model of dopamine system dysfunction]

Hypofunction of the dopamine system was induced by haloperidol or reserpine in Wistar rats. Reserpine increased a number of glial fibrillary acidic protein (GFAP) containing astrocytes by 49% and reduced glutamine synthase astrocytes and monoamine oxidase activity by 23% and 1/3, respectively. Haloperidol had no effect on morpho-chemical characteristics of astrocytes but increased a number of oligodendrocytes. It has been supposed that the activation of astroglia by reserpine in a dopamine hypofunction model is caused by the dysfunction of the corticostriatal glutamatergic system as a result of inhibition of the dopaminergic transmission in the basal nuclei. The changes in the neuroglial interactions in the striatum that lead to the disbalance of neuromediator systems in the basal nuclei may underlie the dysfunction of the basal nuclei in some diseases including Parkinson's disease.

Immunohistochemical and morphological changes in neurons and neuroglia in the cerebral nigrostriatal structures under conditions of experimental nigral neurodegeneration

The count of dopamine-containing neurons decreased by 77%, the area of the remaining cells shrank by 75%, and the neuroglia doubled 4 weeks after injection of toxin (6-hydroxydopamine) into the compact part of the substantia nigra of the right cerebral hemisphere of rats, while no changes in the substantia nigra of the left hemisphere were observed. Neurons of the caudate nucleus were virtually unchanged in comparison with the intact control, while the neuroglia was activated: its total volume in the right hemisphere increased by 33% (50% increase in astrocyte count and a 25% increase of the rest neuroglia), while in the left hemisphere only astrocyte count increased by 20%. Astrocyte nuclei in the caudate nuclei of both hemispheres were enlarged by 22-23%. Hence, unilateral destruction of the nigral dopamine-containing neurons stimulated the neuroglia (particularly astroglia) in the caudate nuclei, especially on the side of damage.

[Age-related dynamics of structure changes in the 17th cortical area of children with perinatal affection of the nervous system]

Brain autopsy of children standing afterperinatal affection of the nervous system and healthy children without any neurological disorders (a control group) has been studied by computers morphometric methods. The age-related dynamics of structure parameters in the 17th cortical area was investigated. Correlation between increasing of cortical lamina's diameters and age of children with perinatal affection of the brain wasn't revealed. The width of IVand V cortical layers, size of neurons and their density in the cortex of children with perinatal pathology were significantly fewer than in the control group. However the density of glia including GFAP-positive astroglia in the children with prenatal pathology was higher to compare with the control group. We suggest that detected disorders are signs of nonspecific structure-functional changes in the visual cortex and follows destructive and compensatory restorative reactions.

[Glial satellites as the source of additional energy supply to the neurons during the increased frequency of firing activity]

Using surviving slices of guinea pig somatosensory cortex, it was shown that functionally different regulation of spontaneous firing activity in different neurons corresponded to irregular distribution of glial satellites. Maximal increase of spike activity induced by acetylcholine (up to 36 spikes per second) was detected in "silent" neurons which account for 37.2% of nerve cells in layer V. According to the morphometric analysis, the same relative number of neurons (38.6%) were surrounded with glial satellites. In spontaneously active neurons only a small elevation of firing activity (5-22 spikes per second) above the basal level was recorded. The results allow to suggest that M-cholinergic reaction, controlling the spontaneous activity level, requires the additional energy supply for its maximal expression in inactive neurons. This is achieved by contacts of neurons with the surrounding glial satellites.

[Risk factors and sequels of perinatal nervous system lesions]

The review of the data available in the literature gives the present views of the causes of perinatal nervous system lesions and risk factors predisposing to the development of this pathology. It also presents the data on different types of lesions of the cerebral cortex, nuclei basalis, and ventricular system, which have been obtained by neuroimaging (computed tomography, magnetic resonance imaging) and morphological studies. The time of intrauterine cerebral periventricular lesion is discussed.

[Investigation of the morphometric parameters of the visual cortical region (Field 17) in perinatal brain damage]

Autopsy brain specimens from babies who had experienced perinatal central nervous system damage and those who had shown no symptoms of brain lesion (a control group) were used to study the structural characteristics of Field 17 of the visual cortical region, by using computed morphometry. As compared with the control group, the children who had suffered from perinatal pathology showed no relationship between the increased width of a cortical plate diameter and the baby's age and Layers I and V had a significantly less width. In most cases Layers III, V and Layer VI + VII contained smaller neurons and the density of their arrangement was much less than in the brain of the control babies. It was concluded that the detected disorders suggest growth retardation and nonspecific structural and functional changes in the visual cortex in perinatal brain damage.

Structural, functional, and biochemical changes in the brain during modeling of dopamine system disturbances in rats

Dysfunction of the dopamine system was modeled in Wistar rats by injection of 50 mg/kg L-dopa over 4 weeks. Experimental rats demonstrated considerably decreased locomotor activity and increased emotional strain compared to the control group. Structural changes consisted in a significant decrease in the size of neuronal bodies in the sensorimotor cortex (layers III and V) and caudate nucleus together with changed variability of these parameters compared to the corresponding values in the control. The neuroglial index increased by 22% in layer V, tended to decrease in layer III, and remained unchanged in the caudate nucleus. L-Dopa changed specific activity of enzymes: tyrosine hydroxylase activity in the sensorimotor cortex decreased by 25%, while monoamine oxidase B activity in the caudate nucleus increased by 33%. Thus, dysfunction of the dopamine system resulting in changes in dopamine metabolism not only leads to structural and functional rearrangements reducing functional capacities of the cell systems, but is also associated with compensatory and repair reactions in the brain.

Structural changes in visual cortex area 17 in children with aftereffects of perinatal injury to the central nervous system

Structural characteristics of the visual cortex area 17 were studied by computer morphometry on autopsied specimens of the brain from children with perinatal injury to the central nervous system and in a group of control children without symptoms of brain injury. In children with perinatal pathology, the thickness of the cortex and its individual layers (IV, V, VI+VII) increased unevenly during the 1st year of life, the density of neurons decreased, while the content of neuroglia increased. These disorders reflect nonspecific structural and functional changes in the visual cortex associated with perinatal cerebral pathology.

[The influence of amphetamine on changes in the brain neuromediator metabolism]

Vistar rats (stress resistant) and August rats (stress-sensitive) were injected with one-time d,l-amphetamine dosages of 1,0 and 2,5 mg/kg. Specific activity of enzymes involved in dopamine and serotonin metabolism - tyrosine hydroxylase, tryptophan hydroxylase, monoaminooxidase, types A and B - was determined and l-dioxyphenylalanine content measured in brain subfractions (sensomotor cortex and striatum). August rats differed from Vistar rats by enzyme activity indices as well as by neuronchemical index expressing a ratio of the specific activity indices of enzymes studied in the sensomotor cortex and the striatum. The neuronchemical index allowed to reveal the characteristic imbalance of dopamine and serotonin metabolism between the cortex and subcortical regions in the brain of August rats that, apparently, determined their stress sensitivity and clearly demonstrated the peculiarities of different amphetamine dosage effect on the animal brain neuromediator metabolism with different stress resistance.

Effect of delta-sleep-inducing peptide on activity of enzymes of biogenic amine metabolism in the brain of Wistar and August rats

Activity of enzymes catalyzing synthesis and degradation of serotonin and dopamine in brain structures of Wistar and August rats was measured biochemically under normal conditions and after short-term exposure to delta-sleep-inducing peptide. The effects of the test peptide manifested in activation of the serotoninergic system and inhibition of the dopaminergic system, particularly in the caudate nucleus. These changes were most pronounced in the brain of Wistar rats.

[Role of morpho-chemical plasticity in the genetic-functional organization of the brain in animals]

Quantitative cytochemistry has revealed that emotional stress-sensitive rats (August) differ from emotional stress-resistant ones (Wistar) in the exchange of neurotransmitters and in the level of protein in the neurons. The differences were found at the level of some brain regions (sensomotor cortex, hippocamp, caudate and adjacent nuclei) and various cells (neurons of the cortex and subcortical structures). It has been concluded that animals of genetically different lines differ not only in behavioral characteristics, but in metabolism in some brain structures.

[Protein cytochemistry in revealing the essentials of the structural and functional organization of the brain]

The histochemical method developed by the author was used to localize lysine- and arginine-rich proteins in the rat, rabbit, feline, canine, and human brains. A great difference was found between neurons (enlarged in lysine-rich proteins) and neuroglia (abundant in arginine-rich proteins). It was suggested that arginine-rich neuroglia might be responsible for or involved in supplying the brain with L-arginine, a precursor of nitric oxide (NO), a secondary messenger that is likely to be used by ancient type neurons. A direct relationship was established between the complexity of the brain structural and functional organization and the increases in lysine-rich neuronal proteins. This assumes that, by analogy with L-arginine synthesis of NO, L-lysine can be a precursor of a hypothetical messenger used by neurons of the higher brain regions. Responses of neurons to experimental exposures were assessed by the changes occurring in the levels of protein and its synthesis. Responses of neurons in the cortex and subcortical areas of the brain were shown to be non-specific and characterized by automatism, but to have specific features in different types of neurons.

[Ammoniacal silver method in alkaline pH range as a technique for detection of morpho-functional features of nerve tissue elements]

An alkaline range pH 9.1-12.3 instead of values pH 7.0-7.1 was used to localize lysine-rich and arginine-rich nucleoproteins by ammonia silver (AS) staining method (Black and Ansley, 1966) in brain structures of rabbits and rats. This modification of AS method made it steady to reveal lysine-rich and arginine-rich nucleoproteins and was able to demonstrate the high variability of protein localization in relation to the balance of essential amino acids in the brain structures with different functions. The best results of morphological staining of nerve, glial cells and their fibres were found at pH 10.6--the point of maximal dissociation of lysine--NH2 groups. At the same time the new modification of AS method allows the use of all alkaline range pH 9.1-12.3 for revealing the cells of nervous tissue and to vary the treatment of sections with silver ions.

[Autoradiography of protein synthesis as a method of assessment of morphofunctional changes in brain structures]

A combination of two groups of autoradiography technique (for a hole brain and individual cells) was applied with using 3H-leucine to evaluate the changes of brain functional activity on the level as anatomical structures and as different type neurons. It was found that Wistar rats with lowered motor activity induced by 3-4 weeks treatment with L-DOPA 100 mg/kg displayed the motor nuclei of the brain stem the cerebellum as highly labelled structures and the motor cortex and n. caudatus as feebly ones in comparison with control. However, a quantitative assessment of silver grains over the neurons of layers III and V of motor cortex and n. caudatus showed not only a significant increase of labelling, especially in neurons of layer V on 174%, in comparison with control but revealed unequal labelling of different type neurons. It was concluded that the applied two groups of autoradiography technique can be a useful approach to assess the brain functional activity.

[Cytochemical research on the effect of a synthetic enkephalin analog on the protein content and enzyme activity of neurons]

Using quantitative cytochemical technique a study was made of the effect of the synthetic analog of the Tyr-D-Ala-Gly-Phe-NH2 on the content and concentration of proteins and on the activity of enzymes (aminopeptidase, glutamate dehydrogenase and acid phosphatase) in neurons of the brain motor cortex and nucleus caudatus of rabbits and rats. The essential changes of the parameters used were registered 3 days after neuropeptide injection. A 30 minutes effects of the synthetic analog of enkephalins in protein metabolism was not so pronounced as a 3 days effect, the former being observed only in neurons of the brain motor cortex. Long-lasting effects of the neuropeptide Tyr-D-Ala-Gly-Phe-NH2 on the metabolism in brain are discussed.

[Total protein content and concentration in the neurons of the "mirror" epileptiform focus in the rat brain at the late stages of its existence]

The experimental lesion in rat brain was produced by the implantation of cobaltogelatin rod into the right parietalis anterior area. A quantitative measurement of total protein was made by microdensitometer in neurons controlateral to cobalt lesion at 112-115 days after cobalt implantation. In the experimental animals, protein content decreased in neurons of lamina III and V area parietalis anterior and the nucleus lateralis thalami by 6, 60 and 53%, resp. It has been concluded that different type neurons have different protein changes in response to paroxyzmal activity at late stages of epileptogenic mirror focus.

[Histone alteration in the nuclei of different types of neurons in a "mirror" epileptiform focus in rat brain]

Total histones estimated after M. Alfred and I. Geschwind were studied cytophotometrically in nuclei of neurons of different types (layers III and V in the frontal-parietal cortex and in the thalamic lateral nucleus) of the "mirror" epileptiform focus in the rat brain on the 11th and 63d day after cobalt implantation. On the 11th day of the experiment, integral optic density of the histones decreased by 33%, 25% and 37%, and the area of the nuclei -- by 27%, 24% and 35% in the neurons of layers II and V in the frontal-parietal cortex and in the thalamic lateral neucleus, respectively. On the 63d, integral optic density of the histones in the neurons mentioned increased respectively by 42%, 52% and 42%, and the area of the nuclei -- by 21%, 43% and 27%. Concentration of the histones in the nuclei decreased by 3--9% on the 11th day and increased, except layer V, by 9--18% on the 63d of the experiment. Interconnection between changes in histone content and total proteins in cytoplasm of functionally different neurons in the "mirror" epileptiform focus is disscussed, with special reference to histones as a regular of genetic activity for protein synthesis.

[Cytochemical characteristics of proteins in the lateral nucleus of the rat thalamus (model of a mirror epileptogenic focus)]

The experimental lesion in rat brain was produced by the implantation of cobalt-gelatin rod into right parietalis anterior area. In this area, paroxymal discharges were determined by electroencephalography on the 11th day after the operation. On the 63rd day, paroxyzmal discharges were more severe. Quantitative measurements of proteins were made by microdensitometer in neurons of nucleus lateralis thalami controlateral to the cobalt lesion. On days 11 and 63 after the operation protein concentrations in the neurons were lowered by 35 and 44%, respectively. The size of neurons of the 11th day supassed the control value by 33%; it demonstrated a tendency to normalization by the 63rd day after cobalt lesion.