The Role of the Hypothalamic Medial Mammillary Nucleus in the Regulation of Respiratory Neurons in Hypoxia

摘要

We studied the influence of stimulation of the medial mammillary (MM) nucleus of the hypothalamus on the impulse activity of respiratory neurons (RN) of the medulla oblongata under normal and oxygen deficiency conditions.Under conditions of normal atmospheric pressure the electrical stimulation of the MM nucleus had mainly an activating influence. In the initial phase, at a 4-5 thousand meter altitude, activation of frequent discharge of neurons occurred. In this situation, stimulation of the MM nucleus induced untypical responses of these neurons. In the second phase (an altitude of 7.5-8 thousand meters) on the reduction of the impulse activity of neurons, stimulation of the MM nucleus of hypothalamus was more accentuated than under conditions of normoxia.The issue of hypoxic conditions in an organism has been and still is one of the urgent problems of biology and medicine. Disturbance of body oxygen homeosta-sis underlies to some extent the pathogenesis of any disease. The issue of hypoxic conditions is especially urgent for our country, because 90% of its territory (including Yerevan, the capital) lies at 1000 m above the sea level. Hence, knowledge of delicate mechanisms of respiratory regulation in hypoxia has not only theoretical but also applied importance.