[Substance P as a factor in resistance to emotional stress].

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].

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.

[Peptide therapy of sleep disorders in neurotic rats].

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.

[Neurono-glial changes in the cerebral cortex of animals exposed to white noise].

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.

[Structural and ultrastructural changes induced by angiotensin II in the cerebral cortex of animals].

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.

[Conditioned reflex, electrographic and mediator-humoral changes during intermittent hypokinesia of different duration in rats].

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.

[Role of the hippocampus in conditioned reflex activity].

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.

[Modeling cerebral dropsy (hydrocephalus) in animals by using angiotensin 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.

[Effect of group and isolated rearing of white rats on their resistance to exposure to emotional stress].

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.