Muscle sympathetic nerve activity during central, mixed and obstructive apnea: are there any differences?

We recorded muscle sympathetic nerve activity (MSNA) from the peroneal nerve during sleep in three OSAS patients who showed three kinds of apnea. During central apneas and central component of mixed apnea, bursts of MSNA appeared in high probability with almost each heart beat. During obstructive apneas and the obstructive component of mixed apneas, bursts of MSNA appeared in a cluster after the end of each inspiratory effort. Burst rate of MSNA during apnea were higher in cental apneas and the central component of mixed apnea than in obstructive apneas and the obstructive component of mixed apneas. These findings indicate that activity in the sympathetic nervous system is enhanced not only in obstructive apnea but also in central and mixed apnea.