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9.4 Reproducibility Patterns of Plasma Noradrenaline and Muscle Sympathetic Nerve Traffic In Human Obesity

  • F. Quarti-Trevano
  • R. Dell’Oro
  • G. Seravalle
  • F. Arenare
  • G. Brambilla
  • V. Ilardo
  • L. Magni
  • G. Grassi
  • G. Mancia
Contributions from International Congress Metabolic Aspects and Mechanisms
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9.4 Reproducibility Patterns of Plasma Noradrenaline and Muscle Sympathetic Nerve Traffic In Human Obesity

Introduction. Regional noradrenaline (NA) spill-over technique and efferent postganglionic muscle sympathetic nerve traffic (MSNA) recording have provided evidence that a hyperadrenergic state is a hallmark of the obese state. In contrast, conflicting are the data obtained on this issue by employing a simpler marker of adrenergic tone such as plasma NA assay.

Aim. The present study has been planned at determining the reproducibility of the two markers of adrenergic drive such as plasma NA and MSNA in reflecting the sympathetic activation characterizing the obese state

Methods. In 15 obese normotensive subjects (age 40.1±2.2 years; mean±SEM) we measured in two experimental sessions spaced each other by a three week interval blood pressure (BP, Finapres), heart rate (EKG), plasma NA (HPLC assay) and MSNA (microneurography, peroneal nerve). We also evaluated anthropometric variables, such as body mass index and waist hip ratio. In each session three NA samples were obtained and NA reproducibility between sessions was assessed by considering single NA samples or averaging 2–3 samples. Reproducibility data were compared to the ones displayed by the MSNA technique.

Results. Average values of systolic BP, diastolic BP, heart rate and MSNA values were almost superimposable in the different recording periods of the two sessions and this was the case also for body mass index and waist-to-hip ratio. While MSNA values showed a highly significant correlation between sessions (r=0.89, p< 0.001), NA values based on a single blood sample evaluation did not correlate each other (r=0.44 p=NS). NA correlation coefficients increased and achieved statistical significance w hen average data from 3 blood samples were examined (r= 0.56, p<0.03).

Conclusions. In human obesity MSNA displays a reproducibility pattern greater than the plasma NA. The reproducibility of NA approach can be improved by increasing the number of blood samples on which NE assay is performed. To obtain such goal, and to make reproducibility closer to the MSNA one, three NA samples are necessary.

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© Adis Data Information BV 2008

Authors and Affiliations

  • F. Quarti-Trevano
    • 1
  • R. Dell’Oro
    • 1
  • G. Seravalle
    • 2
  • F. Arenare
    • 1
  • G. Brambilla
    • 1
  • V. Ilardo
    • 1
  • L. Magni
    • 1
  • G. Grassi
    • 1
  • G. Mancia
    • 1
  1. 1.Università Milano-Bicocca, Ospedale San GerardoMonzaItaly
  2. 2.Istituto Auxologico ItalianoMilanoItaly

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