[Effect of phrenicotomy on extravagal diaphragmatic reflexes].

In experiments on decerebrated or anesthetized with nembutal and vagotomized cats responses of phrenic motoneurons were studied before and after bilateral phrenicotomy. The tracheal occlusion and changes of the lung and chest volumes were used as stimuli. Phrenicotomy did not eliminate the responses. As before the diaphragm denervation, tracheal occlusion evoked only a small shortening of inspiration, extending of the expiration and respiratory cycle, decreasing the amplitude of activity of the phrenic nerve. In response to lung inflation expiration was a little shortened. With lung deflation activity of phrenic motoneurons was not changed. Impulses of the diaphragm mechanoreceptors and excitatory intercostal-to-phrenic reflex from caudal intercostal proprioceptors had no significance in regulation of activity of phrenic motoneurons in response to tracheal occlusion and changes of the lung and chest volumes in decerebrated and anesthetized cats.