[Pathological types of breathing during acute hypoxia]

Different breathing pathologies (apneusis, gasping, Cheyne-Stokes breathing and Kussmaul breathing) were observed in anaesthetized rabbits and rats exposed to hypoxia at the altitude of 7500-8000 meters. Dominance of the high-voltage slow EKG activity (the delta-wave type) suggested deterioration of the brain functioning. Registration of impulse activities of the inspiration and expiration breathing neurons in medulla oblongata revealed a higher tolerance of the inspiration neurons to severe hypoxia which is attributed to the metabolic specifics and functional heterogeneity of these neurons. Character of the neuron impulsation is indicative of the reflectory effects of hemo- and mechanoreceptors, and the direct effects of different humoral substances resulting in impairment of the central control of pacemakers and breathing pathologies. It appears that various breathing pathologies in altitude chambers and mountains are triggered by the hypoxic factor. However, no dependence was established either between the initial breathing rhythm (before "ascent") and various types of breathing at the "altitude" or these types of breathing and magnitude of hypoxia.