Resetting of the sympathetic baroreflex is associated with the onset of hypertension during chronic intermittent hypoxia

Kenta Yamamoto, Wendy Eubank, Michelle Franzke, Steve Wayne Mifflin

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Chronic intermittent hypoxia (CIH) is a model of arterial hypoxemia that accompanies sleep apnea and increases resting arterial pressure (AP). We examined the effects of 7. days of exposure to CIH on arterial baroreflex control of renal sympathetic nerve activity (RSNA) and heart rate (HR) in rats. Sprague-Dawley rats (15. plus/minus 2. weeks old) were exposed to CIH (9% oxygen for 3. min every 10. min, 8. h per day) for 7. days (n = 16) while control rats (n = 18) were maintained in normoxia. Baroreflex regulation of RSNA and HR were estimated in Inactin anesthetized and artificially ventilated rats during infusions of phenylephrine and nitroprusside to manipulate AP. After exposure to CIH, resting mean AP was higher in CIH than that in control group (115 ± 7 vs. 105 ± 7, P. < 0.001). Resting HR did not differ between the two groups. Exposure to CIH shifted the AP-RSNA relationship rightward (approximately 10. mm. Hg, P. < 0.01). CIH did not alter maximum gain of the baroreflex control of RSNA (- 2.6 ± 0.6 vs. - 2.5 ± 0.6 arbitrary units (a.u.)/mm. Hg) and HR (- 1.8 ± 0.6 vs. - 1.8 ± 0.7. bpm/mm. Hg, CIH vs. control). In addition, cardiac spontaneous baroreflex sensitivity in conscious rats (n = 8) also did not change during exposure to CIH. These results indicate that resetting of the sympathetic baroreflex control, rather than an impairment of its sensitivity, is associated with an onset of hypertension induced by CIH.

Original languageEnglish
Pages (from-to)22-27
Number of pages6
JournalAutonomic Neuroscience: Basic and Clinical
Volume173
Issue number1-2
DOIs
StatePublished - 1 Jan 2013

Fingerprint

Baroreflex
Hypertension
Arterial Pressure
Heart Rate
Kidney
Hypoxia
Sleep Apnea Syndromes
Nitroprusside
Phenylephrine
Sprague Dawley Rats
Oxygen

Keywords

  • Baroreflex
  • Hypertension
  • Sleep apnea
  • Sympathetic nerve activity

Cite this

Yamamoto, Kenta ; Eubank, Wendy ; Franzke, Michelle ; Mifflin, Steve Wayne. / Resetting of the sympathetic baroreflex is associated with the onset of hypertension during chronic intermittent hypoxia. In: Autonomic Neuroscience: Basic and Clinical. 2013 ; Vol. 173, No. 1-2. pp. 22-27.
@article{d3eee4a2e6fc4afda9942f691db08e3b,
title = "Resetting of the sympathetic baroreflex is associated with the onset of hypertension during chronic intermittent hypoxia",
abstract = "Chronic intermittent hypoxia (CIH) is a model of arterial hypoxemia that accompanies sleep apnea and increases resting arterial pressure (AP). We examined the effects of 7. days of exposure to CIH on arterial baroreflex control of renal sympathetic nerve activity (RSNA) and heart rate (HR) in rats. Sprague-Dawley rats (15. plus/minus 2. weeks old) were exposed to CIH (9{\%} oxygen for 3. min every 10. min, 8. h per day) for 7. days (n = 16) while control rats (n = 18) were maintained in normoxia. Baroreflex regulation of RSNA and HR were estimated in Inactin anesthetized and artificially ventilated rats during infusions of phenylephrine and nitroprusside to manipulate AP. After exposure to CIH, resting mean AP was higher in CIH than that in control group (115 ± 7 vs. 105 ± 7, P. < 0.001). Resting HR did not differ between the two groups. Exposure to CIH shifted the AP-RSNA relationship rightward (approximately 10. mm. Hg, P. < 0.01). CIH did not alter maximum gain of the baroreflex control of RSNA (- 2.6 ± 0.6 vs. - 2.5 ± 0.6 arbitrary units (a.u.)/mm. Hg) and HR (- 1.8 ± 0.6 vs. - 1.8 ± 0.7. bpm/mm. Hg, CIH vs. control). In addition, cardiac spontaneous baroreflex sensitivity in conscious rats (n = 8) also did not change during exposure to CIH. These results indicate that resetting of the sympathetic baroreflex control, rather than an impairment of its sensitivity, is associated with an onset of hypertension induced by CIH.",
keywords = "Baroreflex, Hypertension, Sleep apnea, Sympathetic nerve activity",
author = "Kenta Yamamoto and Wendy Eubank and Michelle Franzke and Mifflin, {Steve Wayne}",
year = "2013",
month = "1",
day = "1",
doi = "10.1016/j.autneu.2012.10.015",
language = "English",
volume = "173",
pages = "22--27",
journal = "Autonomic Neuroscience: Basic and Clinical",
issn = "1566-0702",
publisher = "Elsevier",
number = "1-2",

}

Resetting of the sympathetic baroreflex is associated with the onset of hypertension during chronic intermittent hypoxia. / Yamamoto, Kenta; Eubank, Wendy; Franzke, Michelle; Mifflin, Steve Wayne.

In: Autonomic Neuroscience: Basic and Clinical, Vol. 173, No. 1-2, 01.01.2013, p. 22-27.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Resetting of the sympathetic baroreflex is associated with the onset of hypertension during chronic intermittent hypoxia

AU - Yamamoto, Kenta

AU - Eubank, Wendy

AU - Franzke, Michelle

AU - Mifflin, Steve Wayne

PY - 2013/1/1

Y1 - 2013/1/1

N2 - Chronic intermittent hypoxia (CIH) is a model of arterial hypoxemia that accompanies sleep apnea and increases resting arterial pressure (AP). We examined the effects of 7. days of exposure to CIH on arterial baroreflex control of renal sympathetic nerve activity (RSNA) and heart rate (HR) in rats. Sprague-Dawley rats (15. plus/minus 2. weeks old) were exposed to CIH (9% oxygen for 3. min every 10. min, 8. h per day) for 7. days (n = 16) while control rats (n = 18) were maintained in normoxia. Baroreflex regulation of RSNA and HR were estimated in Inactin anesthetized and artificially ventilated rats during infusions of phenylephrine and nitroprusside to manipulate AP. After exposure to CIH, resting mean AP was higher in CIH than that in control group (115 ± 7 vs. 105 ± 7, P. < 0.001). Resting HR did not differ between the two groups. Exposure to CIH shifted the AP-RSNA relationship rightward (approximately 10. mm. Hg, P. < 0.01). CIH did not alter maximum gain of the baroreflex control of RSNA (- 2.6 ± 0.6 vs. - 2.5 ± 0.6 arbitrary units (a.u.)/mm. Hg) and HR (- 1.8 ± 0.6 vs. - 1.8 ± 0.7. bpm/mm. Hg, CIH vs. control). In addition, cardiac spontaneous baroreflex sensitivity in conscious rats (n = 8) also did not change during exposure to CIH. These results indicate that resetting of the sympathetic baroreflex control, rather than an impairment of its sensitivity, is associated with an onset of hypertension induced by CIH.

AB - Chronic intermittent hypoxia (CIH) is a model of arterial hypoxemia that accompanies sleep apnea and increases resting arterial pressure (AP). We examined the effects of 7. days of exposure to CIH on arterial baroreflex control of renal sympathetic nerve activity (RSNA) and heart rate (HR) in rats. Sprague-Dawley rats (15. plus/minus 2. weeks old) were exposed to CIH (9% oxygen for 3. min every 10. min, 8. h per day) for 7. days (n = 16) while control rats (n = 18) were maintained in normoxia. Baroreflex regulation of RSNA and HR were estimated in Inactin anesthetized and artificially ventilated rats during infusions of phenylephrine and nitroprusside to manipulate AP. After exposure to CIH, resting mean AP was higher in CIH than that in control group (115 ± 7 vs. 105 ± 7, P. < 0.001). Resting HR did not differ between the two groups. Exposure to CIH shifted the AP-RSNA relationship rightward (approximately 10. mm. Hg, P. < 0.01). CIH did not alter maximum gain of the baroreflex control of RSNA (- 2.6 ± 0.6 vs. - 2.5 ± 0.6 arbitrary units (a.u.)/mm. Hg) and HR (- 1.8 ± 0.6 vs. - 1.8 ± 0.7. bpm/mm. Hg, CIH vs. control). In addition, cardiac spontaneous baroreflex sensitivity in conscious rats (n = 8) also did not change during exposure to CIH. These results indicate that resetting of the sympathetic baroreflex control, rather than an impairment of its sensitivity, is associated with an onset of hypertension induced by CIH.

KW - Baroreflex

KW - Hypertension

KW - Sleep apnea

KW - Sympathetic nerve activity

UR - http://www.scopus.com/inward/record.url?scp=84871490033&partnerID=8YFLogxK

U2 - 10.1016/j.autneu.2012.10.015

DO - 10.1016/j.autneu.2012.10.015

M3 - Article

C2 - 23167993

AN - SCOPUS:84871490033

VL - 173

SP - 22

EP - 27

JO - Autonomic Neuroscience: Basic and Clinical

JF - Autonomic Neuroscience: Basic and Clinical

SN - 1566-0702

IS - 1-2

ER -