[Substance P as a factor in resistance to emotional stress]. / Substantsiia P kak faktor ustoichivosti k emotsional'nomu stressu.

The effect of substance P--an endogenous brain peptide--on the resistance to chronic emotional stress was studied in rats. A single administration of the peptide (125 or 250 mkg/kg) elicits a highly significant increase of rats resistance to chronic emotional stress and reduces the raise of adrenals weight, hemodynamic fluctuations and emotional reactivity.

[Effect of substance P on behavior in the rabbit and the activity of cortical neurons during training]. / Vliianie veshchestva P na povedenie krolikov i aktivnost' neironov kory pri ikh obuchenii.

Subcutaneous injection of substance P to rabbits in a dose of 250 mcg/kg elicited a transitory disappearance of motor reactions to painful reinforcing stimuli and a reduction of their probability to reinforced and inhibitory light flashes, as well as a protracted heart rate increase and decrease of respiration rate. One third of the neurones recorded decreased their background firing level and or excitatory components of the reactions to reinforcement and conditioned light flashes. The decrease was most distinctly seen in the sensorimotor cortex and less pronounced in the visual cortical area and hippocampus. The influence of the substance P on different types of cortical inhibition was not the same. Tonic inhibition of neuronal activity in response to reinforcement was enhanced. Bioelectrical parameters which reflect an enhancement of inhibitory hyperpolarization during elaboration of internal inhibition (i.e. inhibitory firing delays and corresponding background and evoked slow potentials oscillations) were not changed.

[Peptide therapy of sleep disorders in neurotic rats]. / Peptidnaia terapiia rasstroistv sna u nevrotizirovannykh krys.

As a result of chronic stress, anxiety appeared in the rats behaviour, motor activity increased, heart rate quickened, blood pressure raised, conditioned instrumental alimentary reflexes missed, the duration of deep phases of sleep lowered, time of falling asleep became longer, the number of awakening increased. The change in quantitative characteristics of sleep was accompanied by its worsening, especially of rapid sleep. Administration of substance P (SP) eledoisin hexopeptide (EH) (250 mcg/kg), 100-200 mcg/kg of delta sleep peptide and 10 mcg/kg of ethylcrotyl barbiturate improved the rats behaviour and sleep parameters. Calipnon accelerated falling asleep. Delta sleep peptide increased sleep duration. SP and EH restored not only the quantitative characteristics of deep phases of sleep but greatly improved their quality: lowered the blood pressure disrupted tachycardia, normalized the conditioned activity.

[Neurono-glial changes in the cerebral cortex of animals exposed to white noise]. / Neirono-glial'nye izmeneniia v kore bol'shogo mozga zhivotnykh pri vozdeistvii belogo shuma.

The rat acoustic cortex has been studied at light optic and ultrastructural levels under the white noise stimulation. After the noise stimulation for 7 days, micropunctate hemorrhages, proliferation and hypertrophy in cells of microglia and astrocytic glia are noted. After the noise stimulation for 21 days, the neuroglial reaction becomes less pronounced, there are no hemorrhages, a great amount of neurons with peripheral and total chromatolysis appear. In other neurons, as well as in all types of neuroglia the number of primary lysosomes increases, their structure changes. In lysosomes lipofuscin and lipid drops are accumulating, many of lysosomes turning into multivesicular bodies. The destructive changes observed in the neurons and neuroglia underlie prolonged disturbances in the higher neural activity after the noise stimulation is stopped.

[Structural and ultrastructural changes induced by angiotensin II in the cerebral cortex of animals]. / Strukturnye i ul'trastrukturnye izmeneniia v kore golovnogo mozga zhivotnykh, vyzvannye angiotenzinom-II.

Structure of capillaries, pericapillary glia and neurons of the sensomotor cerebral cortex was studied in rats after intraperitoneal injections of angiotensin-II (0.05 mg/kg of the body weight) administered once for 1, 3, 7, 14 and 21 days. The animals were decapitated 5 and 15 min after a single injection, and at repeated injections--15 min after the last one. The repeated injections of angiotensin-II were stated to produce a stable edematous syndrome in the brain of the animals. Pericapillary (astrocytic) glial edema was associated with neural cells edema. The more angiotensin-II was injected, the greater was dilatation of astrocytic processes adjoining the capillaries. In some edematous neurons it was cytoplasmic matrix that swelled, in others--liquid was accumulated in the cytoplasmic network cavities. Membrane bodies appeared in the capillary endothelial cells and in neurons made also a peculiar feature. It could be possible that functional shifts in the CNS observed after repeated injections of angiotensin-II were resulted from deficiency of the cerebral circulation and some structural changes in neural and glial elements.

[Conditioned reflex, electrographic and mediator-humoral changes during intermittent hypokinesia of different duration in rats]. / Uslovnoreflektornye, élektrograficheskie i mediatorno-gumoral'nye izmeneniia pri preryvistoi gipokinezii raznoi dlitel'nosti u krys.

Intermittent hypokinetic stress in rats, lasting from 1 to 6 weeks was attended by a complex of shifts of behavioural, conditioned, bio-electrical and mediator-humoral parameters. They considered as an evidence of the changes occuring in the tonic level of emotional state. Different phases of emotional state follow one another with the progress of hypokinesia. Acute emotional stress is observed, as well as the development of a compensatory systemic reaction and initial symptoms of the exhaustion of adaptational systems.

[Role of the hippocampus in conditioned reflex activity]. / O roli gippokampa v uslovnoreflektornoi deiatel'nosti.

The role of the hippocampus in animals' conditioned activity was studied in experiments on rats and cats with ablated hippocampus. It was shown that in rats the ablation leads to a statistically significant slowing down in learning of the avoidance reaction. The effect becomes stronger in stress situation. The process of learning and optimization of choice reaction in the maze with alimentary reinforcement if sharply impaired in rats with bilateral ablation of hippocampus. The bilateral ablation of the hippocampus in cats in experiments with choice of the side of the alimentary reinforcement prolonged the latencies and sharply increased the number of erroneous reactions. The obtained data are analyzed in terms of fronto-pallido-hippocampal system, which selects, compares and integrates sensory information at the stage of the afferent synthesis.

[Modeling cerebral dropsy (hydrocephalus) in animals by using angiotensin II]. / Modelirovanie vodianki golovnogo mozga (gidrotsefalii) na zhivotnykh s pomoshch'iu angiotenzina-II.

The effect of a synthetic polypeptic hormone angiotensin-II on the structure of the brain ventricular system was studied in rats. A single injection of angiotensin-II, firm "Ciba", was given to rats in a dose of 0.05 mg/kg of body weight on the 1, 3, 7, 14 and 21st days. The brain was extirpated 15 min after the last injection, fixed in formalin and embedded in celloidin. Intact animals served as controls. A single injection of angiotensin-II was found to be accompanied by a slight dilatation of the brain lateral ventricles. Seven injections resulted in further accumulation of the fluid in the ventricles, and the first symptoms of the corpus callosum atrophy appeared. After the 21st injection of angiotensin-II a typical picture of hydrocephalus demonstrating further accumulation of the fluid in the brain ventricles was seen. The atrophic changes were especially pronounced in the corpus callosum, in white and grey substances of the frontal lobes of the cerebral hemispheres. Besides the atrophic changes, angiotensin-II-induced hydrocephalus resulted in subependymic edema, exfoliation of ependymal cells--the features characteristic for other types of hydrocephalus. Thus, injections of the synthetic hormone angiotensin-II can facilitate in producing an experimental atraumatic hydrocephalus. By means of angiotensin-II a desirable degree of hydrocephalus can be obtained by changing the dose of the preparation.

[Effect of group and isolated rearing of white rats on their resistance to exposure to emotional stress]. / Vliianie gruppogo i izolirovannogo vyrashchivaniia belykh krys na ustoichivost' k vozdeistviiu émotsional'nogo stressa

The influence of isolated vs. group breeding on the sensitivity of higher nervous and vegetative functions to chronic stress effects was studied in 50 albino random-bred male rats. It has been found that group breeding of the animals (ten specimens in each cage) from the 12th to the 30th week of their life enhances their resistance to external stress factors which begin to take effect from the 17th week on. The effect is linked to the positive emotions produced by mutual contacts among the animals and their intensified motor activity. Isolated breeding of the rats (beginning with the 17th week of their life) makes them vulnerable to the action of stress situations. By the end of the investigation they exhibit clear symptoms of an early stage of neurogenic hypertension. The isolation evidently sets up a negative emotional background, reduces drastically the motor activity and lowers the animals resistance to extreme environmental influences.