[Oxygenation of the frontal cerebral cortex in monkeys during a two-week space flight].

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.

[The effect of acoustic cavitation on the contraction force and membrane potential of rat papillary muscles].

Acoustic cavitation induced by continuous focused ultrasound (1.4 W/cm2, 543 Hz) was found to result in reversible membrane depolarization (by 54 mV), loss of excitability and contracture in the rat papillary muscles. The same intensities of impulse ultrasound had positive inotropic effects.

[The action of ultrasound on the contraction strength and action potential of the papillary muscle of the rat heart].

In experiments on isolated rat papillary muscles the effects of therapeutic doses of ultrasound (US) (intensity, less than 2 W/cm2) with frequency of 0.88 MHz on contraction force and action potential (AP) were studied. 12 muscles (from 14) responded to 3-min exposition of the US with a rise both in contraction force and in resting tension.

[Mechanisms of enkephalin action on learning and memory processes].

The influence of enkephalin on the processes of elaboration and preservation of the defensive conditioned reflexes of bilateral avoidance (CRBA) and conditioned reflexes of passive avoidance (CRPA) in intact rats and animals with changed functional state of serotoninergic system of the brain has been examined. Injection of enkephalin in dose of 10 mkg to intact animals accelerated the elaboration of CRBA not influencing in this case their preservation, but deeply disturbed the CRPA preservation. The excess of serotonin in the brain created by means of 5-oxytryptophan fully prevented the acceleration of CRBA elaboration by enkephalin under the usual conditions.