Limb congestion enhances the synchronization of sympathetic outflow with muscle contraction

Sogol Mostoufi-Moab, Michael D. Herr, David Silber, Kristen S. Gray, Urs Leuenberger, Lawrence Sinoway

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

In this report, we examined if the synchronization of muscle sympathetic nerve activity (MSNA) with muscle contraction is enhanced by limb congestion. To explore this relationship, we applied signal-averaging techniques to the MSNA signal obtained during short bouts of forearm contraction (2-s contraction/3-s rest cycle) at 40% maximal voluntary contraction for 5 min. We performed this analysis before and after forearm venous congestion; an intervention that augments the autonomic response to sustained static muscle contractions via a local effect on muscle afferents. There was an increased percentage of the MSNA noted during second 2 of the 5-s contraction/rest cycles. The percentage of total MSNA seen during this particular second increased from minute 1 to 5 of contraction and was increased further by limb congestion (control minute 1 = 25.6 ± 2.0%, minute 5 = 32.8 ± 2.2%; limb congestion minute 1 = 29.3 ± 2.1%, minute 5 = 37.8 ± 3.9%; exercise main effect <0.005; limb congestion main effect P = 0.054). These changes in the distribution of signal-averaged MSNA were seen despite the fact that the mean number of sympathetic discharges did not increase over baseline. We conclude that synchronization of contraction and MSNA is seen during short repetitive bouts of handgrip. The sensitizing effect of contraction time and limb congestion are apparently due to feedback from muscle afferents within the exercising muscle.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume279
Issue number2 48-2
StatePublished - Sep 20 2000

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Muscle Contraction
Extremities
Muscles
Forearm
Hyperemia

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)

Cite this

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title = "Limb congestion enhances the synchronization of sympathetic outflow with muscle contraction",
abstract = "In this report, we examined if the synchronization of muscle sympathetic nerve activity (MSNA) with muscle contraction is enhanced by limb congestion. To explore this relationship, we applied signal-averaging techniques to the MSNA signal obtained during short bouts of forearm contraction (2-s contraction/3-s rest cycle) at 40{\%} maximal voluntary contraction for 5 min. We performed this analysis before and after forearm venous congestion; an intervention that augments the autonomic response to sustained static muscle contractions via a local effect on muscle afferents. There was an increased percentage of the MSNA noted during second 2 of the 5-s contraction/rest cycles. The percentage of total MSNA seen during this particular second increased from minute 1 to 5 of contraction and was increased further by limb congestion (control minute 1 = 25.6 ± 2.0{\%}, minute 5 = 32.8 ± 2.2{\%}; limb congestion minute 1 = 29.3 ± 2.1{\%}, minute 5 = 37.8 ± 3.9{\%}; exercise main effect <0.005; limb congestion main effect P = 0.054). These changes in the distribution of signal-averaged MSNA were seen despite the fact that the mean number of sympathetic discharges did not increase over baseline. We conclude that synchronization of contraction and MSNA is seen during short repetitive bouts of handgrip. The sensitizing effect of contraction time and limb congestion are apparently due to feedback from muscle afferents within the exercising muscle.",
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Limb congestion enhances the synchronization of sympathetic outflow with muscle contraction. / Mostoufi-Moab, Sogol; Herr, Michael D.; Silber, David; Gray, Kristen S.; Leuenberger, Urs; Sinoway, Lawrence.

In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 279, No. 2 48-2, 20.09.2000.

Research output: Contribution to journalArticle

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