[Respiratory center function in the course of the cough reflex in normoxia and hypoxia]

Impulse activity of the medulla respiratory neurons and electrical activity of the diaphragm and intercostal muscles were studied prior to, during and after coughing fit in anesthetized cats under conditions of normoxia and hypoxia. Simultaneously the intrapleural pressure was recorded and O2, paCO2, SaO2 were determined in arterial blood. Massive excitation of inspiratory and expiratory neurons as well as considerable augmentation of respiratory muscles electrical activity occurred during coughing fit. Soon after the fit the activity of neurons and muscles restored to initial level. During acute hypoxia the coughing fit shortened, the coughing seizures weakened as compared with the normoxic conditions. After the coughing fit, in result of hyperventilation during the fit, the paCO2 sharply dropped in arterial blood, the neuronal volley activity and the muscles rhythmic activity became disorganized, and apnea occurred. Within 20-40 sec rhythmic volley activity of the medulla inspiratory neurons disrupted the apnea.