American journal of physiology. Regulatory, integrative and comparative physiology
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Am. J. Physiol. Regul. Integr. Comp. Physiol. · Nov 2010
Randomized Controlled Trial Multicenter StudyVentilatory restraint of sympathetic activity during chemoreflex stress.
The within-breath modulation of muscle sympathetic nerve activity (MSNA) is well established, with greater activity occurring during expiration and less during inspiration. Whether ventilation per se affects the longer-term (i.e., minute-to-minute) regulation of MSNA has not been determined. We sought to define the specific role of ventilation in regulating sympathetic activation during chemoreflex activation, where both ventilation and MSNA are increased. ⋯ The augmented sympathetic response during apneas was associated with a larger pressor response and total peripheral resistance compared with rebreathing. These data demonstrate that ventilation per se restrains sympathetic activation during chemoreflex activation. Further, the augmented sympathetic response during apneas was associated with greater cardiovascular stress and may be relevant to the cardiovascular pathology associated with sleep-disordered breathing.