[Heart functions in monkeys during a 2-week antiorthostatic hypokinesia]. / Funktsii serdtsa u obez'ian vo vremia dvukhnedel'noi antiortostaticheskoi gipokinezii.

Dynamics of the left heart ventricular muscle contractility and compliance was studied in 4 monkeys in the head down position (antiorthostatic hypokinesia) with the body angle 10 during 2 weeks. Functional tests on a tilt table and under two conditions of centrifuge rotation were performed prior to and after the antiorthostatic hypokinesia. No changes in the left heart ventricular muscle contractility was found. However, the sensitivity level of the baroreflex control decreased. Compliance of the left heart myocardial fibre increased in the first hours and days of the antiorthostatic hypokinesia.

[Oxygenation of the frontal cerebral cortex in monkeys during a two-week space flight]. / Kislorodnyi rezhim lobnoi kory golovnogo mozga obezíany v protsesse 2-nedelnogo kosmicheskogo poleta.

In monkeys (Macaca mulatta) during a two-week space flight and in a ground-based control experiment, with semi-closed platinum electrodes, partial oxygen pressure (pO2) was registered in the frontal cerebral cortex. It was shown that during the flight there is a marked increase of pO2 in the frontal cortex, reaching maximal values on days 5-8 (up to 203%) with a subsequent tendency to normalization by day 11. In the control experiment pO2 values in the cortical zone studied did not exceed the baseline level throughout the period of registration. Analysis of the curves of pO2 oscillations in the frequency range from 0.2 to 0.01 Hz in-flight revealed a shift of the oscillation power spectrum in the long-wave direction which was not seen in the control experiment and suggested a decreased rate of tissue metabolism. As a possible explanation for the noted effects of pO2 dynamics during weightlessness, a combination of a decreased metabolic rate in the brain segment under study with a disorder in the mechanism of regulation of local cerebral blood flow is suggested.

[Influence of vestibular and afferent impulses on the spontaneous activity of interneurons in the spinal cord of cats]. / Vliianie vestibuliarnoi i afferentnoi impul'satsii na spontannuiu aktivnost' promezhutochnykh neironov spinnogo mozga koshki

Responses of the cat spinal interneurons were studied under electrical stimulation of dorsal roots and adequate stimulation of vestibular apparatus. The evoked activity of interneurons in response to electrical stimulation of dorsal roots had different forms. Three types of responses to adequate stimulation of vestibular apparatus were observed. The patterns of convergence of afferent and vestibular impulses on the interneurons are discussed.