Effect of barodenervation on c-Fos expression in the medulla induced by static muscle contraction in cats

L. I. Jianhua, Jeffrey T. Potts, Jere H. Mitchell

Research output: Contribution to journalArticlepeer-review

Abstract

A previous study has shown increased Fos-like immunoreactivity (FLI), a marker of neural activation, in the nucleus of the solitary tract (NTS) and the ventrolateral medulla (VLM) after static muscle contraction elicited by electrical stimulation of L7 and Si ventral roots of the spinal cord in anesthetized, baroreceptor-intact cats. Because the electrically induced static muscle contraction reflexly increased arterial blood pressure, the concomitant activation of the arterial baroreceptor reflex during static muscle contraction may have resulted in some of the FLI labeling that was observed in the medulla. The purpose of this study was to determine regions in the medulla that are activated by muscle contraction in the absence of arterial baroreceptor input. Electrical stimulation of LY and Si ventral roots of the spinal cord was used to elicit static muscle contraction, and FLI in the medulla was determined in barointact and barodenervated cats. In barointact contraction cats, FLI was observed in the lateral reticular nucleus (LRN), NTS, lateral tegmental field (FTL), subretrofacial nucleus (SRF), and Al region of the medulla. In barodener.vated contraction cats, FLI increased in the same regions; however, the number of FLI-labeled cells in the NTS, FTL, and Al region was significantly less than in barointact contraction animals. No significant difference in the number of FLI-labeled cells was found in the LRN and SRF between the two groups. These results clearly demonstrate that cardiovascular regions in the medulla are activated by input from afferent activity originating in skeletal muscle independently of concomitant arterial baroreceptor reflex activation.

Original languageEnglish (US)
JournalAmerican Journal of Physiology
Volume274
Issue number3 PART 2
StatePublished - 1998

Keywords

  • Exercise pressor reflex
  • Heart rate
  • Nucleus of the solitary tract
  • Ventrolateral medulla

ASJC Scopus subject areas

  • Physiology (medical)

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