title: The effect of chemoreceptor stimulation upon muscle sympathetic nerve activity.
abstract: The aim of this investigation was to quantify the combined peripheral and central chemoreceptor contribution to sympathetic outflow above (post) and below (pre) the chemoreceptor ventilatory threshold (CVT). We measured muscle sympathetic nerve activity (MSNA) in seven subjects during hypoxic/hypercapnic and room air rebreathe protocols. Comparisons were made using a repeated measures analysis of variance with two within subject factors. One factor contained three levels--hyperventilation, pre-CVT, and post-CVT. The other factor contained two levels--rebreathe and control. Total MSNA increased from hyperventilation to pre-CVT to post-CVT in the rebreathe trial (385.7+/-95.9, 592.4+/-155.7, 882.0+/-235.4 au/15s respectively) and remained constant in the control trial (433.0+/-189.3, 409.1+/-183.4, 406.1+/-161.4 au/15s respectively). Ventilation increased in the rebreathe trial only. Heart rate and blood pressure did not change in either trial. These data suggest that the chemoreceptors significantly contribute to the modulation of sympathetic outflow.
authors.affiliation: Department of Rehabilitation Medicine, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA. Ggates@montefiore.org
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Gates
authors.forename: Matthew N
authors.initials: MN
authors.lastname: Bartels
authors.forename: John A
authors.initials: JA
authors.lastname: Downey
authors.forename: Ronald E
authors.initials: RE
authors.lastname: De Meersman
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000097:blood; D002490:Central Nervous System / Q000502:physiology; D002628:Chemoreceptor Cells / Q000187:drug effects / Q000502:physiology*; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology; D006985:Hyperventilation / Q000503:physiopathology; D000860:Hypoxia / Q000503:physiopathology; D008297:Male; D017933:Peripheral Nervous System / Q000502:physiology; D012132:Respiratory Muscles / Q000294:innervation* / Q000502:physiology; D013268:Stimulation, Chemical; D013564:Sympathetic Nervous System / Q000502:physiology*; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide