[Hemodynamic structure of antiorthostatic reactions: relationship of mechanical activity of the heart and arterial pressure].
In acute experiments with antiorthostatic rats tilt-induced changes in the parameters of cardiac activity (left ventricle systolic pressure (LVPs), its first derivative dp/dt, end-diastolic pressure (EDP) were compared in relation to the directionality and extent of systolic (sAP) and diastolic arterial pressure (dAP) shifts. Rise of the tilt angle by 15-45 degrees reduced sAP and dAP, increased LVPs and EDP and did not influence dp/dt. Changes in the cardiac parameters and AP were not unidirectional; sAP and dAP shifts were asynchronous. In a special experimental series, higher tilt angle was found to bring about opposite changes in cardiac ejection (CE) and total peripheral resistance (TPR). Growth in CE was concurrent to a progressive decline in TPR. Discussed is the response of the vascular system to antiorthostasis the unique character of which is vasodilatation.
Osadchiĭ
L I
LI
Balueva
T V
TV
Sergeev
I V
IV
D000818:Animals; D001794:Blood Pressure; D018475:Head-Down Tilt; D006321:Heart / Q000502:physiology*; D006439:Hemodynamics; D011187:Posture; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar
Gemodinamicheskaia struktura antiortostaticheskikh reaktsiĭ: sootnosheniia mekhanicheskoĭ aktivnosti serdtsa i arterial'nogo davleniia.