Release of substance P in the nucleus tractus solitarius measured by in vivo microdialysis: response to stimulation of the aortic depressor nerves in rabbit

David A. Morilak, Margaret Morris, John Chalmers

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

Substance P (SP) is found in high concentration in the nucleus tractus solitarius (NTS), and is a neurotransmitter candidate in primary baroreceptor afferents to the NTS. Release of SP in the medial NTS of halothane-anesthetized rabbits was measured by in vivo microdialysis. Bilateral electrical stimulation of the aortic depressor nerves (ADN) elicited a significant elevation in SP collected during the period following stimulation, while sham stimulation had no effect. Perfusion through the dialysis probe with a high-potassium (150 mM) solution caused a large increase in the level of SP collected, verifying the neural origin of this release. Possible explanations for the delay in increased release of SP include interaction with carotid afferents, diffusion time, or excitation of SP-containing inputs to the NTS originating elsewhere in the brain. This study demonstrates that SP release in the NTS is elevated by activation of baroreceptor afferents, supporting the hypothesis that SP plays a role in the central integration of cardiovascular control. Whether this relase is from primary afferent terminals, or from another source, remains to be seen.

Original languageEnglish (US)
Pages (from-to)131-137
Number of pages7
JournalNeuroscience Letters
Volume94
Issue number1-2
DOIs
StatePublished - Nov 22 1988
Externally publishedYes

Keywords

  • Aortic depressor nerve
  • Baroreflex
  • Microdialysis
  • Neuropeptide
  • Neurotransmitter release
  • Nucleus tractus solitarii
  • Substance P

ASJC Scopus subject areas

  • Neuroscience(all)

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