[Effect of antiorthostatic hypokinesia and its combination with +Gz runs on the otolith regulation of cardiac rhythm in primates].
Amplitude of cardiac rhythm response to the otolith stimulus (AR-R), i.e. rapid reduction of the EKG R-R interval was determined in 24 Macacas mulatta before and after 28-d head-down (-6 degrees) immobilization (HDI). In two experimental series the animals were divided into 2 groups (control and CF) with 6 primates in each. In the HDI series-1, the CF animals were rotated on a centrifuge with a 3.62-m arm at 1.2 up to 1.6 +Gz for 30-40 minutes 4-5 times a week. In HDI series-2, the CF animals were rotated 30 min at 1.2 +Gz 2-3 times a week. In a day after HDI, AR-R was significantly reduced in both CF groups, which, when compared with EKG R-R intervals, suggests attenuation of equally parasympathetic and sympathetic influences on the heart. In 7 days since HDI, AR-R was close to baseline values in control primates on both series and CF primates in series-2, whereas in the CF group in series-2 AR-R exceeded baseline values. Significant differences in mean AR-R values in the control and CF groups in series-1 following 7 days after HDI point to the prophylactic effect of small but regular g-loads manifested in more rapid recovery of initial level of the cardiac rhythm regulation.
Badakva
A M
AM
Miller
N V
NV
Riazanskiĭ
S N
SN
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology*; D002498:Centrifugation; D004562:Electrocardiography; D006339:Heart Rate / Q000502:physiology*; D018476:Hypokinesia / Q000503:physiopathology*; D008253:Macaca mulatta; D008297:Male; D013997:Time Factors; D014893:Weightlessness