[Electrophysiological characteristics of animal respiratory muscles after long-term stay at high altitudes].

Experiments were made using rats at different stages of readaptation after long-term stay at high altitudes. Characteristics of bioelectrical activity of respiratory muscles were obtained for the first time, its spectral picture is described in different periods of readaptation.

[The characteristics of breathing regulation in animals after sympathectomy procedures during alpine adaptation]. / Osobennosti reguliatsii dykhaniia u zhivotnykh na fone desimpatiziruiushchikh vozdeistvii v protsesse gornoi adaptatsii.

Physiological parameters were studied at the 760 and 3200-metres altitudes in chemically desympathised (25 mg guanethidine per kg during 30 days) albino rats. Changes in external respiratory function were found to be less obvious at the higher altitude.

[The protective action of different types and regimens of adaptation to hypoxia on the development of stress-induced lesions in KM strain (Krushinskii-Molodkina) rats]. / Protektornoe deistvie raznykh vidov i rezhimov adaptasii k gipoksii na razvitie stressovykh povrezhdenii u krys linii KM.

The effect of preliminary adaptation to hypoxia on the development of stress-induced lesions was studied on the model of acoustic stress in the Krushinskii-Molodkina line rats genetically predisposed to audiogenic seizures. At different regimens of adaptation to hypoxia (long- and short-term, continuous, intermittent), a decrease of the death rate, severity of motor disorders, incidence and degree of intracranial hemorrhages occurred. Only when using a hypoxic gas mixture, a reduction of excitability of the c.n.s. was revealed: the latency increased whereas the intensity of the seizure decreased. Two-hour normobaric hypoxic stimulation prevented an increase in the lipid peroxidation products and contributed to a rise of cyclic nucleotides concentration in the brain hemispheres of the KM line rats exposed to acoustic stress.

[Spirograph for small laboratory animals]. / Spirograf dlia melkikh laboratornykh zhivotnykh.

A design of dry spirograph is described. It is characterized by greater precision, lack of inertia, high reliability, absence of respiration resistance, adequate form of recording, rapid resetting to any respiratory rate. The device consists of two similar injection syringes, photoelectric sensor for the identification of the initial moments of respiration stages, electromagnetic valves, two photoelectric converters of the air volume into the impulse signal, vacuum micro-pump, microcompressor and a system of air-driving tubes. In the initial position of pistons and valves the microcompressor pumps air into the inhalation cylinder and lifts the piston to the upper extreme position. With the signal marking the beginning of inspiration, the valves switch over and the piston lowers, pushing out the air, which moves into the animals' respiratory organs. Simultaneously, the signals of the inhaled air volume from the photoelectric transducer reach the recorder. During expiration the air pushes the piston down into the second cylinder and photoelectric transducer gives the information on the volume of the expired air.

[Dynamics of various characteristics of the sympathetic ganglia of animals subjected to chemical sympathectomy at high altitude]. / Dinamika nekotorykh kharakteristik simpaticheskikh gangliev zhivotnykh, podvergnutykh khimicheskoi desimpatizatsii v usloviiakh vysokogor'ia.

The effect of high altitude hypoxia on the sympathetic nervous system was studied on desympathized rats. The degree of the sympathetic ganglion neurons destruction and catecholamine fluorescence were determined. The investigation showed an increase of catecholamine fluorescence in sympathetic ganglia in high altitude adaptation. 30-day administration of sympatholytic guanethidine at high altitude results in destruction of less ganglion neurons than at low altitude. At high altitude the rate of fluorescence of biogenic amines in unaffected cells remains high. After partial desympathization (7 days), the rate of neuron destruction diminishes and biogenic amines fluorescence increases along with the duration of preliminary adaptation.