TY - JOUR
T1 - Periods of intermittent hypoxic apnea can alter chemoreflex control of sympathetic nerve activity in humans
AU - Cutler, Michael J.
AU - Swift, Nicolette Muenter
AU - Keller, David M.
AU - Wasmund, Wendy L.
AU - Burk, John R.
AU - Smith, Michael L.
PY - 2004/11
Y1 - 2004/11
N2 - Obstructive sleep apnea is associated with sustained elevation of muscle sympathetic nerve activity (MSNA) and altered chemoreflex control of MSNA, both of which likely play an important role in the development of hypertension in these patients. Additionally, short-term exposure to intermittent hypoxic apneas can produce a sustained elevation of MSNA. Therefore, we tested the hypothesis that 20 min of intermittent hypoxic apneas can alter chemoreflex control of MSNA. Twenty-one subjects were randomly assigned to one of three groups (hypoxic apnea, hypercapnic hypoxia, and isocapnic hypoxia). Subjects were exposed to 30 s of the perturbation every minute for 20 min. Chemoreflex control of MSNA was assessed during baseline, 1 min posttreatment, and every 15 min throughout 180 min of recovery by the MSNA response to a single hypoxic apnea. Recovery hypoxic apneas were matched to a baseline hypoxic apnea with a similar nadir oxygen saturation. A significant main effect for chemoreflex control of MSNA was observed after 20 min of intermittent hypoxic apneas (P < 0.001). The MSNA response to a single hypoxic apnea was attenuated 1 min postexposure compared with baseline (P < 0.001), became augmented within 30 min of recovery, and remained augmented through 165 min of recovery (P < 0.05). Comparison of treatment groups revealed no differences in the chemoreflex control of MSNA during recovery (P = 0.69). These data support the hypothesis that 20 min of intermittent hypoxic apneas can alter chemoreflex control of MSNA. Furthermore, this response appears to be mediated by hypoxia.
AB - Obstructive sleep apnea is associated with sustained elevation of muscle sympathetic nerve activity (MSNA) and altered chemoreflex control of MSNA, both of which likely play an important role in the development of hypertension in these patients. Additionally, short-term exposure to intermittent hypoxic apneas can produce a sustained elevation of MSNA. Therefore, we tested the hypothesis that 20 min of intermittent hypoxic apneas can alter chemoreflex control of MSNA. Twenty-one subjects were randomly assigned to one of three groups (hypoxic apnea, hypercapnic hypoxia, and isocapnic hypoxia). Subjects were exposed to 30 s of the perturbation every minute for 20 min. Chemoreflex control of MSNA was assessed during baseline, 1 min posttreatment, and every 15 min throughout 180 min of recovery by the MSNA response to a single hypoxic apnea. Recovery hypoxic apneas were matched to a baseline hypoxic apnea with a similar nadir oxygen saturation. A significant main effect for chemoreflex control of MSNA was observed after 20 min of intermittent hypoxic apneas (P < 0.001). The MSNA response to a single hypoxic apnea was attenuated 1 min postexposure compared with baseline (P < 0.001), became augmented within 30 min of recovery, and remained augmented through 165 min of recovery (P < 0.05). Comparison of treatment groups revealed no differences in the chemoreflex control of MSNA during recovery (P = 0.69). These data support the hypothesis that 20 min of intermittent hypoxic apneas can alter chemoreflex control of MSNA. Furthermore, this response appears to be mediated by hypoxia.
KW - Obstructive sleep apnea
KW - Sympathetic nerve activity
UR - http://www.scopus.com/inward/record.url?scp=7244221285&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.00377.2004
DO - 10.1152/ajpheart.00377.2004
M3 - Article
C2 - 15242836
AN - SCOPUS:7244221285
SN - 0363-6135
VL - 287
SP - H2054-H2060
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 5 56-5
ER -