Blood-flow and pO2 in the posterior hypothalamus of cats during paradoxical sleep.

It was found in chronic experiments in cats, using the recording of local blood flow and oxygen tension (pO2) in the anterior and posterior hypothalamus in the sleep-wakefulness cycle, that when the phases of sleep are alternated, the changes in these parameters are in different directions: the level of blood flow and the frequency of fluctuation of the pO2 during paradoxical sleep increase in the posterior hypothalamus, while they decrease in the anterior hypothalamus. On the other hand, the opposite pattern is observed during slow-wave sleep. The multidirectionality of the changes in local blood flow level and in the frequency of fluctuations of pO2 in one and the same sleep phase indicate that they are of local origin and must be governed by functional-metabolic shifts in these structures; the functional state of the posterior hypothalamus during paradoxical sleep is assessed on this basis.