Baroreflex modulation of muscle sympathetic nerve activity during posthandgrip muscle ischemia in humans

Jian Cui, Thad E. Wilson, Manabu Shibasaki, Nicole A. Hodges, Craig G. Crandall

Research output: Contribution to journalArticlepeer-review

64 Scopus citations

Abstract

To identify whether muscle metaboreceptor stimulation alters baroreflex control of muscle sympathetic nerve activity (MSNA), MSNA, beat-by-beat arterial blood pressure (Finapres), and electrocardiogram were recorded in 11 healthy subjects in the supine position. Subjects performed 2 min of isometric handgrip exercise at 40% of maximal voluntary contraction followed by 2.5 min of posthandgrip muscle ischemia. During muscle ischemia, blood pressure was lowered and then raised by intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure was more negative (P < 0.001) during posthandgrip muscle ischemia (-201.9 ± 20.4 units·beat-1·' mmHg-1) when compared with control conditions (-142.7 ± 17.3 units·beat-1·mmHg-1). No significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. However, both curves shifted during postexercise ischemia to accommodate the elevation in blood pressure and MSNA that occurs with this condition. These data suggest that the sensitivity of baroreflex modulation of MSNA is elevated by muscle metaboreceptor stimulation, whereas the sensitivity of baroreflex of modulate heart rate is unchanged during posthandgrip muscle ischemia.

Original languageEnglish (US)
Pages (from-to)1679-1686
Number of pages8
JournalJournal of applied physiology
Volume91
Issue number4
DOIs
StatePublished - 2001

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)

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