Capsaicin-induced reflex fall in rat blood pressure is mediated by afferent substance P-containing neurones via a reflex centre in the brain stem

Naunyn Schmiedebergs Arch Pharmacol. 1983 Dec;324(4):293-5. doi: 10.1007/BF00502626.

Abstract

Injection of 0.03 micrograms capsaicin into one femoral artery elicited a fall in blood pressure in the rat. This effect was completely and reversibly abolished following intrathecal injection of 1 nmol of the specific substance P antagonist, [D-Pro2,D-Trp7,9] substance P. The capsaicin-evoked depressor reflex is therefore exclusively mediated by substance P-containing primary afferent fibres. Using spinal rats or decerebration experiments, the centre of the capsaicin-evoked reflex fall in blood pressure could be localized in the brain stem.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Pressure / drug effects*
  • Brain Stem / drug effects
  • Capsaicin / pharmacology*
  • Decerebrate State
  • Injections, Intra-Arterial
  • Injections, Spinal
  • Male
  • Neurons, Afferent / drug effects*
  • Rats
  • Reflex / drug effects
  • Substance P / analogs & derivatives
  • Substance P / antagonists & inhibitors*
  • Substance P / pharmacology

Substances

  • Substance P
  • substance P, prolyl(2)-tryptophan(7,9)-
  • Capsaicin