Responses of blood pressure and renal sympathetic nerve activity to colorectal distension in anesthetized rats

Weimin M. Li, A. Suzuki, K. M. Cui

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

We investigated the effects of visceral stimulation by colorectal distension (CRD) on mean arterial blood pressure (MAP) and renal sympathetic nerve activity (RSNA), the latter being an index of vasoconstrictor activity, in anesthetized central nervous system (CNS)-intact and C2 spinalized rats. The CRD stimulation was induced by the distention of a balloon inserted into the colorectum. In CNS-intact rats, there were significant reductions in MAP and RSNA in response to intraballoon pressures of 60 and 80 mmHg, but not to 20 and 40 mmHg. However, spinalized rats demonstrated significant increases in MAP in response to intraballoon pressures of 60 and 80 mmHg and increases in RSNA in response to intraballoon pressures of 40, 60, and 80 mmHg. These results suggest that noxious visceral stimulation at lower spinal levels reduces MAP by inhibiting sympathetic output in CNS-intact anesthetized rats. On the other hand, noxious visceral stimulation results in an increase in sympathetic-induced MAP in spinalized anesthetized rats.

Original languageEnglish (US)
Pages (from-to)153-156
Number of pages4
JournalJournal of Physiological Sciences
Volume56
Issue number2
DOIs
StatePublished - Apr 2006

Keywords

  • Colorectal distention
  • Mean arterial blood pressure
  • Rats
  • Renal sympathetic nerve activity

ASJC Scopus subject areas

  • Physiology

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