title: Muscle sympathetic nerve activity is related to a surrogate marker of endothelial function in healthy individuals.
abstract: BACKGROUND
  Evidence from animal studies indicates the importance of an interaction between the sympathetic nervous system and the endothelium for cardiovascular regulation. However the interaction between these two systems remains largely unexplored in humans. The aim of this study was to investigate whether directly recorded sympathetic vasoconstrictor outflow is related to a surrogate marker of endothelial function in healthy individuals.
  
  
  RESULTS
  In 10 healthy normotensive subjects (3 f/7 m), (age 37+/-11 yrs), (BMI 24+/-3 kg/m(2)) direct recordings of sympathetic action potentials to the muscle vascular bed (MSNA) were performed and endothelial function estimated with the Reactive Hyperaemia- Peripheral Arterial Tonometry (RH-PAT) technique. Blood samples were taken and time spent on leisure-time physical activities was estimated. In all subjects the rate between resting flow and the maximum flow, the Reactive Hyperemic index (RH-PAT index), was within the normal range (1.9-3.3) and MSNA was as expected for age and gender (13-44 burst/minute). RH-PAT index was inversely related to MSNA (r = -0.8, p = 0.005). RH-PAT index and MSNA were reciprocally related to time (h/week) spent on physical activity (p = 0.005 and p = 0.006 respectively) and platelet concentration (PLT) (p = 0.02 and p = 0.004 respectively).
  
  
  CONCLUSIONS
  Our results show that sympathetic nerve activity is related to a surrogate marker of endothelial function in healthy normotensive individuals, indicating that sympathetic outflow may be modulated by changes in endothelial function. In this study time spent on physical activity is identified as a predictor of sympathetic nerve activity and endothelial function in a group of healthy individuals. The results are of importance in understanding mechanisms underlying sympathetic activation in conditions associated with endothelial dysfunction and emphasise the importance of a daily exercise routine for maintenance of cardiovascular health.
authors.affiliation: Institute of Neuroscience and Physiology, Department of Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. yrsa.sverrisdottir@neuro.gu.se
authors.forename: Yrsa Bergmann
authors.initials: YB
authors.lastname: Sverrisdóttir
authors.forename: Linda Marie
authors.initials: LM
authors.lastname: Jansson
authors.forename: Ulrika
authors.initials: U
authors.lastname: Hägg
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Gan
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D001053:Apolipoproteins / Q000097:blood; D015415:Biomarkers / Q000032:analysis* / Q000097:blood; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight; D002784:Cholesterol / Q000097:blood; D004730:Endothelium, Vascular / Q000502:physiology*; D004815:Epidermal Growth Factor / Q000097:blood; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D018482:Muscle, Skeletal / Q000294:innervation*; D013564:Sympathetic Nervous System / Q000502:physiology*; D014280:Triglycerides / Q000097:blood; D055815:Young Adult
chemical_list: D001053:Apolipoproteins; D015415:Biomarkers; D014280:Triglycerides; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D002784:Cholesterol