MLR stimulation and exercise pressor reflex activate different renal sympathetic fibers in decerebrate cats

Shawn G. Hayes, Marc P Kaufman

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

Although mesencephalic locomotor region (MLR) stimulation and the exercise pressor reflex have been shown to increase whole nerve renal sympathetic activity, it is not known whether these mechanisms converge onto the same population of renal sympathetic postganglionic efferents. In decerebrate cats, we examined the responses of single renal sympathetic postganglionic efferents to stimulation of the MLR and the exercise pressor reflex (i.e., static contraction of the triceps surae muscles). We found that, in most instances (24 of 28 fibers), either MLR stimulation or the muscle reflex, but not both, increased the discharge of renal postganglionic sympathetic efferents. In addition, we found that renal sympathetic efferents that responded to static contraction while the muscles were freely perfused responded more vigorously to static contraction during circulatory arrest. Moreover, stretch of the calcaneal (Achilles) tendon stimulated the same renal sympathetic efferents as did static contraction. These findings suggest that MLR stimulation and the exercise pressor reflex do not converge onto the same renal sympathetic postganglionic efferents.

Original languageEnglish (US)
Pages (from-to)1628-1634
Number of pages7
JournalJournal of Applied Physiology
Volume92
Issue number4
StatePublished - 2002

Keywords

  • Autonomic nervous system
  • Central command
  • Exercise
  • Mesencephalic locomoter region
  • Static contraction
  • Tendon stretch

ASJC Scopus subject areas

  • Endocrinology
  • Physiology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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