[Neutral peptide hydrolase activity in human blood in hypoxia].

Athletes were taken to an altitude of 2100 m and allowed to get adapted to the highland environment for a month. Then blood serum neutral peptide-hydrolases were measured at rest and after exercise. Also, metabolic and respiratory parameters were investigated.

[Physical work capacity of Alpinists under conditions of extremely low pO2 in inspired air].

It is shown that high-trained Alpinists retain relatively high working capacity under conditions of extremely low piO2. Maximal oxygen uptake with extremely low piO2 decreases in high-trained Alpinists less than the working capacity which under conditions of extremely low piO2, is, mainly, limited by decreased potentiality to utilize oxygen by cardiac and skeletal muscles because of paO2 and pvO2 fall below critical values. Low paO2 promotes a decrease in the rate of oxygen diffusion from blood of capillaries into cells, fall of oxygen tension in tissues and lowering of the oxidative processes' rate.

[Effect of blockers of pre- and post-synaptic inhibition on processes of habituation in the system of cutaneous sensitivity].

The role of pre- and postsynaptic inhibition in the habituation of spinal ascending neurons transmitting cutaneous sensory signals was studied in cat. Pharmacological blockade of these types of inhibition by strychnine, bicuculline and picrotoxin did not evoke substantial changes in initial suppression of neuronal discharges during prolonged high-frequency (more than 50 per s) stimulation. Neuronal responses to stimulation of a cutaneous nerve fibres were not influenced during habituation of the neuron evoked by stimulation of other converging cutaneous nerve fibres.

[Transmission of impulse trains by nerve fibers upon near-threshold stimulation].

Impulse trains evoked by stimulation of the hindlimb nerves were studied in group A fibres at the lumbar level of spinal cord in anesthetized cats. Random (Poissonian) trains fo stimuli and trains with modified structure were used. With suprathreshold stimulation the impulse trains in the nerve fibres differed from the stimulus trains only by the absence of the shortest (less than 1.