Characterization of neurokinin-1 receptors in the submucosal plexus of guinea pig ileum

B. A. Moore, S. Vanner, N. W. Bunnett, K. A. Sharkey

Research output: Contribution to journalArticle

Abstract

This study combined immunohistochemical double-labeling techniques with functional studies to characterize the neurokinin-1 (NK1) receptors mediating neuronal and vasodilator responses in submucosal guinea pig ileum. NK1 receptor distribution in whole mount preparations of the submucosa was examined using a rabbit polyclonal antibody directed against the COOH terminus of the rat NK1 receptor. Results showed that 97% of neuropeptide Y immunoreactive submucosal neurons colocalized NK1 receptor immunoreactivity, whereas vasoactive intestinal polypeptide immunoreactive neurons were not NK1 immunoreactive. Intracellular recordings were made using neurobiotin- filled electrodes to enable reidentification of recorded neurons for immunohistochemical study. The selective NK1 agonists [Sar9,Met(O2)11]substance P (SP) and septide depolarized S-type submucosal neurons. Of these neurons, 36% were NK1 immunoreactive and 64% were not. NK1 immunoreactivity was not observed on submucosal arterioles, but superfusion of [Sar9,Met(O2)11]SP and septide dilated preconstricted submucosal arterioles. Agonist-evoked responses in both neurons and blood vessels were blocked by the selective NK1 antagonist CP-99994. These findings suggest that NK1 receptors are found on submucosal neurons and arterioles and that electrophysiological and immunohistochemical techniques may identify conformational variants of the receptor.

Original languageEnglish (US)
Pages (from-to)G670-G678
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume273
Issue number3 36-3
DOIs
StatePublished - Sep 1997

Keywords

  • Blood flow
  • Secretion
  • Substance P
  • Tachykinin receptors

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

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