Stress hypertension in monkeys.

1. The influence of chronic forelimb immobilization enforcing movement in upright position on blood pressure was studied in monkeys. 2. In the course of 6 months all animals subjected to immobilization became hypertensive due to a parallel increase of systolic and diastolic pressure by about 30%. The hypertension was demonstrable both in awake and anaesthetized animals and persisted even after restitution of a normal movement regime. 3. In the chronic stage (after 15 months), the plasma renin concentration was decreased by 55%, indicating that the renin-angiotensin system activation does not participate in the maintenance of the hypertensive state. The plasma volume was diminished by 18%, while the interstitial fluid volume did not differ significantly from control values. 4. It is concluded that chronic forelimb immobilization in monkeys induces a low-renin hypertension, associated with changes in extracellular fluid compartments resembling the pattern found in the hypovolaemic type of essential hypertension.

[Anthropophysiologic basis of the formation of arterial hypertension in primates]. / Antropofiziologicheskaia osnova formirovaniia arterial'noi gipertonii u primatov.

Comparative physiological analysis suggested evolutional direction of typical organization of the blood orthostatic regulation and its dependence upon the posture status in pronograde animals (rats, rabbits, cats, dogs) as well as in primates (humans, monkeys). Data on the evidence of functional adaptation of cardiovascular system under the conditions of experimental bipedal posture in monkeys are presented and the meaning of blood regulation according to the gravity factor in the development of arterial hypertension is discussed.

[Typologic characteristics of central hemodynamics in the monkey in reclining and upright positions]. / Tipologicheskaia kharakteristika tsentral'noi gemodinamiki u obez'ian v klino- i ortostatike.

By tetrapolar rheography central hemodynamics was investigated in 74 rhesus monkeys in the reclining and orthostatic position. The basic hemodynamic parameters were examined in relation to the entire sample, to the groups with a higher or lower blood pressure (BPmean), and to four states of central circulation in orthostatic animals. The typological circulatory differences in the orthostatic state were shown to be determined by qualitatively different hemodynamic mechanisms responsible for BPmean. The hemodynamic characteristics in the reclining and orthostatic position were found to be reciprocally related. It is recommended to take into consideration the typological differences of hemodynamics that can modify cardiovascular responses to various effects.