Changes in hemodynamics and respiration in rats with different resistance to acute hypoxia

Differences in Tolerance to Hypoxia: Physiological, Biochemical, and Molecular-Biological Characteristics

Hypoxia plays an important role in the development of many infectious, inflammatory, and tumor diseases. The predisposition to such disorders is mostly provided by differences in basic tolerance to oxygen deficiency, which we discuss in this review. Except the direct exposure of different-severity hypoxia in decompression chambers or in highland conditions, there are no alternative methods for determining organism tolerance. Due to the variability of the detection methods, differences in many parameters between tolerant and susceptible organisms are still not well-characterized, but some of them can serve as biomarkers of susceptibility to hypoxia. At the moment, several potential biomarkers in conditions after hypoxic exposure have been identified both in experimental animals and humans. The main potential biomarkers are Hypoxia-Inducible Factor (HIF)-1, Heat-Shock Protein 70 (HSP70), and NO. Due to the different mechanisms of various high-altitude diseases, biomarkers may not be highly specific and universal. Therefore, it is extremely important to conduct research on hypoxia susceptibility biomarkers. Moreover, it is important to develop a method for the evaluation of organisms' basic hypoxia tolerance without the necessity of any oxygen deficiency exposure. This can contribute to new personalized medicine approaches' development for diagnostics and the treatment of inflammatory and tumor diseases, taking into account hypoxia tolerance differences.

Effect of picrotoxin on organism's resistance to acute severe hypoxia

Organism's resistance to acute severe hypoxia (3% O2) was studied after administration of GABA(A) receptor antagonist picrotoxin and adenosine receptor antagonist euphylline (aminophylline) and after neutralization of secondary hypocapnia by adding 7% CO2 to the hypoxic mixture. Administration of picrotoxin to anesthetized rats increased animal resistance to hypoxia. The resistance to hypoxia decreased after treatment with euphylline. Neutralization of secondary hypocapnia by adding 7% CO2 to the hypoxic mixture had no effect on animal lifespan.

Effect of lithium hydroxybutyrate on hemodynamics and respiration in rats with different resistance to hypoxia

Acute experiments on narcotized rats showed that intravenous infusion of GABA derivative lithium hydroxybutyrate induced different changes in hemodynamic and respiratory parameters in animals with high and low resistance to hypoxia. Rats highly resistant to hypoxia better tolerated lithium hydroxybutyrate treatment compared to low resistant animals.