Sleep-wake state organization in infant rats with episodic respiratory disturbance following sinoaortic denervation

The role of arterial chemoreceptors in the maintenance of rhythmic respiration during sleep was investigated in 2-week-old rats by microsurgical sectioning of carotid sinus and aortic depressor nerve fibers (SAD) and later recording of respiratory pattern by impedance pneumography and sleep-wake states by electrophysiological methods. Deafferentation produced high rates of an atypical respiratory pattern characterized by episodes during which the usual pattern was replaced by an arrhythmic series of low amplitude waveforms with frequent short pauses and occasional gasps. These episodes lasted a mean of 20s, occurred 15.1 times/h and were virtually confined to the REM state. Apneas occurred in all stages of sleep and were not increased by SAD but were significantly associated with state changes only after denervation. Body movements were unchanged and sleep-wake state organization was only minimally affected by SAD. These results suggest that the REM state may constitute a vulnerable period for respiratory control in infancy during which afferent feedback from peripheral arterial chemoreceptors may ordinarily play a stabilizing role.