Direct evidence for tonic sympathetic support of resting metabolic rate in healthy adult humans

Mary Beth Monroe, Douglas R. Seals, Linda F. Shapiro, Christopher Bell, David Johnson, Pamela Parker Jones

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71 Scopus citations

Abstract

The sympathetic nervous system (SNS) plays an important role in the regulation of energy expenditure. However, whether tonic SNS activity contributes to resting metabolic rate (RMR) in healthy adult humans is controversial, with the majority of studies showing no effect. We hypothesized that an intravenous propranolol infusion designed to achieve complete β-adrenergic blockade would result in a significant acute decrease in RMR in healthy adults. RMR (ventilated hood, indirect calorimetry) was measured in 29 healthy adults (15 males, 14 females) before and during complete β-adrenergic blockade documented by plasma propranolol concentrations ≥100 ng/ml, lack of heart rate response to isoproterenol, and a plateau in RMR with increased doses of propranolol. Propranolol infusion evoked an acute decrease in RMR (-71 ± 11 kcal/day; -5 ± 0.7%, P < 0.0001), whereas RMR was unchanged from baseline levels during a saline control infusion (P > 0.05). The response to propranolol differed from the response to saline control (P < 0.01). The absolute and percent decreases in RMR with propranolol were modestly related to baseline plasma concentration of norepinephrine (r = 0.38, P = 0.05; r = 0.44, P = 0.02, respectively). These findings provide direct evidence for the concept of tonic sympathetic β-adrenergic support of RMR in healthy nonobese adults.

Original languageEnglish (US)
Pages (from-to)E740-E744
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume280
Issue number5 43-5
StatePublished - May 2001

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Keywords

  • Resting energy metabolism
  • Sympathetic nervous system
  • β-adrenergic blockade

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Physiology (medical)

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