title: Circadian variations of stellate ganglion nerve activity in ambulatory dogs.
abstract: BACKGROUND
  The presence of circadian variations in sympathetic outflow from the stellate ganglia is unclear.
  
  
  OBJECTIVE
  The purpose of this study was to continuously record stellate ganglion nerve activity (SGNA) in ambulatory dogs.
  
  
  METHODS
  We performed continuous 24-hour left (N = 3) or bilateral (N = 3) SGNA recordings in normal ambulatory dogs using implanted Data Sciences International transmitters. We also performed simultaneous ECG recording (n = 5) or simultaneous ECG and blood pressure recordings (n = 1).
  
  
  RESULTS
  The total duration of continuous ambulatory recording averaged 41.5 +/- 16.6 days. Five dogs had persistent stable recording, and one dog developed hardware malfunction in week 3. SGNA was followed immediately (<1 second) by heart rate and blood pressure elevation and a reduced standard deviation of consecutive activation cycle length (SDNN) from 236 +/- 93 ms to 121 +/- 51 ms (P = 0.007). Heart rate correlated significantly with SGNA. When there was a sudden increase of SGNA, the sudden increase occurred bilaterally in 90% of the episodes. Both heart rate and SGNA showed statistically significant (P <.01) circadian variation. Nadolol (20 mg/day for 5 days) reduced average heart rate from 99 +/- 8 bpm at baseline to 88 +/- 9 bpm (N = 6, P = .001) but did not significantly alter SGNA. Immunohistochemical staining of the stellate ganglia showed tyrosine hydroxylase-positive ganglion cells and nerves at the recording site.
  
  
  CONCLUSIONS
  There is a circadian variation in sympathetic outflow from canine stellate ganglia. Circadian variation of SGNA is an important cause of circadian variations of cardiac sympathetic tone.
authors.affiliation: Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, CA 90048-1865, USA.
authors.forename: Byung-Chun
authors.initials: BC
authors.lastname: Jung
authors.forename: Amish S
authors.initials: AS
authors.lastname: Dave
authors.forename: Alex Y
authors.initials: AY
authors.lastname: Tan
authors.forename: Ghassan
authors.initials: G
authors.lastname: Gholmieh
authors.forename: Shengmei
authors.initials: S
authors.lastname: Zhou
authors.forename: David C
authors.initials: DC
authors.lastname: Wang
authors.forename: A George
authors.initials: AG
authors.lastname: Akingba
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Fishbein
authors.forename: Carlo
authors.initials: C
authors.lastname: Montemagno
authors.forename: Shien-Fong
authors.initials: SF
authors.lastname: Lin
authors.forename: Lan S
authors.initials: LS
authors.lastname: Chen
authors.forename: Peng-Sheng
authors.initials: PS
authors.lastname: Chen
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D004285:Dogs; D004558:Electric Stimulation; D004562:Electrocardiography; D004567:Electrodes, Implanted; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D007150:Immunohistochemistry; D008991:Monitoring, Physiologic; D009248:Nadolol / Q000494:pharmacology; D013233:Stellate Ganglion / Q000473:pathology / Q000503:physiopathology*; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D000319:Adrenergic beta-Antagonists; D009248:Nadolol; D014446:Tyrosine 3-Monooxygenase