[Immobilization stress-induced changes in catecholamine levels in the individual cerebral nuclei in rats of different zoosocial ranks]. / Vyzvannye immobilizatsionnym stressom izmeneniia urovnia katekhola- minov otdel'nykh iader mozga krys, razlichaiushchikhsia po zoo- sotsial'nomu rangu.

Immobilization stress induced catecholamines level changes were studied in brain nuclei, taking part in blood pressure central regulation in rats with different zoosocial position. The significant differences in catecholamines level between the zoosocial groups of rats were shown in dopamine synthesized hypothalamic nuclei-n. arcuatus, n. periventricularis and noradrenaline synthesized-n. subcoeruleus++. The dominant rats were characterized by the highest catecholamines level.

[The role of catecholamines in various brain nuclei in maintaining the stability of physiological functions in emotional stress]. / Rol' katekholaminov otdel'nykh iader mozga v podderzhanii ustoichivosti fiziologicheskikh funktsii pri émotsional'nom stresse

Direct arterial BP recording through an indwelling catheter in the tail artery showed August rats to be more prone to disorders of arterial BP control under emotional stress, as compared to Wistar rats. High baselines of catecholamines, dopamine in particular, in the cerebral nuclei, and the involvement of zone A1 adrenalin BP control are unfavorable indicators of a predisposition to abrupt BP changes in response to stress. Locus ceruleus is shown to play an essential role in BP control under emotional stress, its functions being largely determined by genetic mechanisms.

[Open-field behavior of rats following bilateral coagulation of the locus coeruleus]. / Povedenie krys v otkrytom pole posle bilateral'noi koaguliatsii sinego piatna.

A modified open-field test was used in the experiments on rats. It was shown that animals 6 days after bilateral coagulation of locus coeruleus displayed weight changes and some behavioural parameters distinct from those of sham-operated and control animals. The most pronounced differences observed in animals after locus coeruleus coagulation, as compared to the control, were inversion and adaptive responses to a sudden brief stimulus, locomotor dysfunction and absence of response to handling.

[Catecholamines in nuclei of the brains of the August strain rat during immobilization stress]. / Katekholaminy v iadrakh mozga krys linii Avgust pri immobilizatsionnom stresse.

Changes in epinephrine, norepinephrine and dopamine levels in different brain nuclei of the August rats were studied after 6.5-hr immobilization. The linkage between the BP dynamics under emotional stress and changes of catecholamines content was observed in epinephrinsynthetizing area A1, norepinephrinsynthetizing area A6 (locus Coeruleus) and dopaminsynthetizing area A9 (substantia nigra). Sharp increase of the BP in the August rats was related to obvious decrease of epinephrine content in A1, norepinephrine in locus coeruleus and dopamine in substantia nigra. The data obtained suggest that deficit of the catecholamines due to the metabolic changes during emotional stress may result in distutbances of the cardiovascular functions control in the August rats.

[Emotional stress-induced changes in catecholamines in the nuclei of the brains of rats differing in "open-field" behavior]. / Vyzvannye emotsional'nym stressom izmeneniia katekholaminov v iadrakh mozga krys, razlichaiushchikhsia po povedeniiu v "otkrytom pole".

The open-field test was used to study the role of initial emotionality in participation of brain catecholamines (CAs) in the BP control under emotional stress. The rats different in emotionality differed from each other in the level of CAs in single brain nuclei under normal conditions. Under stress, opposite CAs changes occurred in rats differing by their initial emotionality, in noradrenaline-synthetizing brain nuclei only. The neurochemical processes (features) which took part in the central BP control under stress were different in rats differing in their initial emotionality.

[Acetylcholinesterase and choline acetyltransferase in the nervous system of rabbits resistant to emotional stress]. / Atsetilkholinesteraza i kholinatsetiltransferaza v nervnoi sisteme krolikov, ustoichivykh k émotsional'nomu stressu.

To study the role of acetylcholine metabolism system in the mechanisms responsible for animals' resistance to emotional stress, the activity of acetylcholinesterase (AChE), butyrylcholinesterase and cholinacetyltransferase (CAT) was evaluated in brain structures and autonomous vegetative nervous system of rabbits after experimental emotional stress. In the course of experiments, arterial pressure and heart rate were recorded. The rabbits whose cardiovascular functions appeared to be resistant showed an increase in the activity of AChE and CAT in the perifocal area of the hypothalamus. It is suggested that the involvement of the perifocal area of the hypothalamus in the formation of the mechanisms responsible for the resistance is linked with the effects on water-salt metabolism.

[Changes in the level of catecholamines in norepinephrine-producing structures of the brain of rats subjected to immobilization]. / Izmeneniia urovnia katekholaminov v noradrenalinsinteziruiushchikh strukturakh mozga krys posle immobilizatsii.

Radioenzymatic assay was used to determine the catecholamine content in locus ceruleus and n. subceruleus in Wistar rats after 6.5-hour immobilization. During immobilization the arterial blood pressure was measured, whereas the state of the gastric mucosa was assessed after the decapitation. Locus ceruleus showed definite correlations of changes in the catecholamine content to the time course of the arterial pressure in the course of immobilization. Upon arterial pressure deviations towards one or another side there was an increase in the content of noradrenaline and dopamine, with this increase being more abrupt during blood pressure elevation. In relatively stable arterial pressure, the level of catecholamines in locus ceruleus does not virtually differ from the control one.

[Plasma catecholamines of August and Wistar strain rats subjected to emotional stress]. / Katekholaminy plazmy krovi u krys linii Avgust i Vistar pri émotsional'nom stressa.

Plasma catecholamine (CA) were measured in August and Wistar rats before and during immobilization. A catheter was inserted into the tail artery to permit direct measurement of blood pressure (BP). The BP was the same in August and Wistar Understress as in control rats. The CA level was higher in August rats. Adrenaline and noradrenaline contents differed in rats of these strains which suggested different release of CAs from the adrenal medulla and sympathetic neurons in these rats during immobilization. The stability of BP under emotional stress was mostly correlated with the lower control level of plasma CAs and with their slightly increased level during immobilization.

[Catecholamines and plasma renin activity of the Koletskii strain of rats under emotional stress]. / Katekholaminy i reninovaia aktivnost' plazmy krovi krys linii Koletskogo pri émotsional'nom stresse.

Koletsky rats differ from Wistar rats by a significantly higher initial arterial blood pressure (AP) and by the increased plasma renin activity. The plasma noradrenaline level in control obese Koletsky rats is also significantly higher than that in Wister rats. There are also considerable differences in the time course of changes in the tests characteristics of rats of both lines during immobilization. AP in Koletsky rats decreases within 120 min of immobilization while in Wistar rats it remains virtually unchanged. Within the first minutes of immobilization plasma renin activity rises, and attains a significantly higher level in Koletsky rats than in Wistar rats. In the later periods of immobilization the strains showed differences in the blood catecholamine content, particularly in that of noradrenaline, a higher content being found in Koletsky rats.

[Catecholamines in the brain structures of rats responding differently to the "open field" test]. / Katekholaminy v strukturakh mozga krys, razlichaiushchikhsia po testu "otkrytogo polia".

Wistar rats divided into groups according to the open-field test showed essential differences in the catecholamine level in 3 out of eight principal catecholamine-synthesizing brain nuclei. In rats with a sharp decrease in crossing and rearing seen throughout the experiment, the adrenaline and dopamine levels in A1 area were significantly higher and the dopamine level in locus ceruleus and n. arcuatus was lower as compared with rats which were not so emotional. It is suggested that the open-field behavior of Wistar rats correlates with the brain catecholamine interplay, the main part being played by adrenaline-synthesizing neurons of A1 area, noradrenaline-synthesizing neurons of locus ceruleus and dopamine-synthesizing neurons of n. arcuatus.

[Changes in the catecholamine content in adrenaline-synthetizing structures of the medulla oblongata in rats with different reactions to long-term immobilization]. / Izmeneniia urovnia katekholaminov v adrenalinsinteziruiushchikh strukturakh prodolgovatogo mozga krys, razlichnym obrazom reagiruiushchikh na dlitel'nuiu odnorazovuiu immobilizatsiiu.

Substantial individual variations of some indices studied were found as a result of comparing catecholamine changes after 6.5-hours' immobilization at A1 and A2 regions of Wistar rat oblongata and in the solitary tract nucleus with abnormal arterial blood pressure and stomach mucosa. The most pronounced catecholamine alterations, manifesting in epinephrine level fall after immobilization, were seen at A1 region. The degree of epinephrine level lowering at A1 region does not correlate with peculiarities of the changed blood pressure or stomach mucosa. It is suggested that A1 region participates in organization of the total component of stress reaction.