[Effect of hypothalamus and amygdala on the impulse activity of neurons of the medullary respiratory center in rats during hypoxia].

Investigations into the role of the hypothalamus nuclei (dorsomedial and posthypothalamic) and amygdala (cortical and central) in regulation of impulse activity of medullary respiratory neurons and respiration as a whole revealed: a) phasic changes of there exponents in hypoxia; b) variety effect of excitation (activation, inhibition) due to stimulation of the structures. At the initial stage of hypoxia (the altitude of 4000-5000 m) hypoxic activation of the impulse discharge made moderating effect of stimulation more expressed as compared with the initial stage of hypoxia. At maximal altitudes (7500-8000 m) inhibition of respiratory neurons occurred and respiration grew slow and superficial. It is noteworthy that on this background stimulation of hypothalamus and amygdala caused more marked moderating effect when compared with the initial stage. This is apparently associated with disengaging of inhibitory effects of cortex on subcortical structures and increased influence of limbic structures on the bulbar respiratory center.