[The effect of opiate receptor ligands on emotional cardiovascular reactions in lower primates]. / Vliianie ligandov opiatnykh retseptorov na émotsiogennye reaktsii serdechno-sosudistoi sistemy u nizshikh primatov.

Intravenous naloxone injection (0.1 mg/kg) facilitated blood pressure increase in response to conditioned sound stimulus followed by electrocutaneous shock in conscious chair-restrained baboons (Papio hamadryas). Naloxone at a dose of 1.0 mg/kg had an opposite effect and led to the decrease in blood pressure and heart rate in conditioned fear reflex. Naloxone microinjections (50 microM) into the periventricular hypothalamus led to a significant diminution of blood pressure and heart rate increment in response to electrocutaneous shock; naloxone microinjections into tractus solitarius nuclei suppressed blood pressure and heart rate reactions both to conditioned (sound) and unconditioned (electrocutaneous shock) stimuli. Microinjections of equimolar morphine quantities in these brain regions facilitated such reactions. It is concluded that endogenous opioid system participates in the formation of cardiovascular reactions to emotional stimuli in monkeys, with multiple opioid receptors of periventricular hypothalamus and tractus solitarius nuclei involved in the generation of such reactions.

[Participation of the endogenous opioid system in the formation of the body's response to stress]. / Uchastie endogennoi opioidnoi sistemy v formirovanii otvetnoi reaktsii organizma na stressovye vozdeistviia.

Autonomic responses to acute stressors in unanesthetized, chair-restrained baboons and macacas include elevations in heart rate, blood pressure and respiratory rate. Naloxone, in a dose of 1.0 mg/kg intravenously, as well as morphine (1.0 mg/kg) suppresses autonomic alterations produced by the introduction of conditioned and unconditioned stimuli. When given in a dose of 0.1 mg/kg, naloxone, on the contrary, facilitates autonomic responses. The autonomic changes induced by electrical stimulation of the medial hypothalamus and nucleus tractus solitarius are influenced by naloxone--in both doses--and by morphine in the opposite manner. These data, as well as those derived from experiments on the effects of micro-injections of naloxone and morphine into the medial hypothalamus and nucleus tractus solitarius suggest that the endogenous opioid system is necessary to display complete autonomic response pattern in monkeys. A hypothesis is proposed to the effect that endogenous opioid system is important for establishing a precise correspondence between the body's potentialities and behavior, and environmental demands.

Blood pressure in monkeys chronically exposed to psycho-emotional stress.

The influence of experimental neurosis due to repeated conflict situations on blood pressure was studied in male monkeys. All animals developed hypertension demonstrable in the conscious state but which disappeared under pentobarbital anaesthesia. Both in conscious and anaesthetized animals, the pulse pressure was in-elevated. The hypertension was accompanied by increased plasma volume to interstitial volume ratio, due to a decrease of the interstitial fluid compartment. The plasma renin concentration was not raised. It is suggested that chronic increase in blood pressure might be responsible for the decrease in compliance of large arteries (as evidenced by increased pulse pressure). This form of hypertension does not depend on the activity of the renin-angiotensin system.

[Beta-endorphin-like immunoreactivity of the blood plasma of hamadryas baboons and its changes]. / Beta-éndorfinopodobnaia immunoreaktivnost' plazmy krovi pavianov gamadrilov i ee izmeneniia.

It was established that plasma level of beta-endorphin-like IR in baboons (Papio hamadryas) was 8 +/- 1 fM/ml, and of beta-lipoprotein-like IR- 9 +/- 1 fM/ml. Ratio between beta-endorphin-like and beta-lipoprotein-like IR was 0.9 +/- 0.1. Under the electrical stimulation of the periventricular-perifornical area of hypothalamus, the level of beta EP-IR reached 26 +/- 9 fM/ml while the level of beta LP-IR fell. On the mamillary hypothalamic area stimulating, no similar changes were observed. A considerable increase in the beta EP-IR level, up to 53 +/- 2 fM/ml, was recorded in hemorrhagic shock. Levels of plasma beta EP-IR in baboons and in men are concluded to be close and the increase of them associated with the stress status of baboons.

[Effect of motor activity on the development of arrhythmia in experimental emotional stress]. / Vliianie dvigatel'noi aktivnosti na vozniknovlenie serdechnykh aritmii pri eksperimental'nom émotsional'nom stresse.

Studies on monkeys and rabbits have shown that the experimental emotional stress can produce various disorders of cardiac rhythm: sinus tachycardia, atrial fibrillation, ventricular extrasystoles and paroxysmal ventricular tachysystoles. In these conditions the adrenaline content in the blood and myocardium is increased 3-4 times, the noradrenaline level is raised in the blood and decreased in the myocardium. Moderate motor activity leads to a relative decrease of adrenaline in the myocardium and arrest of cardiac arrhythmias. Marked motor activity on the contrary leads to an increase of the adrenaline and noradrenaline level in the myocardium and to the development of disorders of cardiac rhythm even up to ventricular fibrillation.

[Cardiac contraction frequency in Macaca rhesus monkeys occupying different position in a group hierarchy]. / Chastota serdechnykh sokrashenii makakov rezusov, zanimaiushchikh raznoe polozhenie v gruppovoi ierarkhii.

Four variants of heart rate ratio were revealed in 8 groups of the monkeys of different hierarchic positions. Dependence of the heart rate in low-ranking monkeys on the character of their interrelationships with the dominant individual, was shown. The lowest heart rate was revealed in the monkeys protected by the drominand individual. The heart rate at rest and its shifts during feeding reflect the degree of emotional tension in monkeys of different ranks.