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The correlation between the pattern of a neuron's reaction to acute hypoxia and individual resistance to oxygen deficit is studied on rats in vivo as well as on surviving slices of their cerebellum in vitro. According to the survival time in a pressure chamber simulating an altitude of 11 km all the rats were divided into groups of high resistance, medium resistance, and low resistance to hypoxia. Survival time was 4.2 times longer in the high resistance group than in the low resistance group. I n the cerebeUar slices of high resistance animals 61.5% high-resistance neurons and 38.5% low-resistance neurons were recorded. On the other hand, in the high resistance animals the percentage of highresistance neurons and low-resistance neurons was 31.2 and 68.8, respectively. The period of hypoxia development was 4.32 tLrnes longer in the high-resistance neurons as compared to low-resistance neurons. It is speculated that individual differences in the resistance to O: deficit are of a hereditary nature and manifest themselves not only on the level of the whole organism, but also in the individual nerve cell. Key Words: hypoxia; individual resistance; neuronsIt is known that during acute oxygen deficiency the first to be affected is the central nervous system, and hypoxia resistance, according to Palladird [10], is defined not by the vulnerability of liver cells but rather by the sensitivity of neurons. The selectivity of nerve cell damage in hypoxia was first described by C. and O. Vogt [13], who introduced the term "pathoclisis', attributing the individual susceptibility of neurons mostly to specific features of vascularization and possibly also of nervous tissue metabolism. Later the same conclusions were r e a c h e d by other investigators [9,11,12,14]. A nonuniform pattern of response of neurons from different regions of the hippocampus to increasing hypoxia has been detected [8]. The Department of Normal Physiology, Russian People's Friendship University, Moscow existence of a correlation between the resistance of an individual organism as a whole and of an individual nerve cell to hypoxia remains an open question.The goal of this work was to study the relationship between the response of individual neurons in surviving brain slices and of the organism as a whole to increasing hypoxia. MATERIALS AND METHODSThe experiments were carried out on alert male white rats and their surviving cerebellar slices of 300-400 g thickness. In order to determine the individual resistance to hypoxia the animals were "raised" in a pressure chamber to an altitude of 11 km at a rate of 150-200 m/sec. The resistance was estimated by the survival time (ST) at a given

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