Contractile responses induced by physalaemin, an analogue of substance P, in the rat esophagus

Takahiko Shiina, Takeshi Shima, Haruko Hirayama, Hirofumi Kuramoto, Tadashi Takewaki, Yasutake Shimizu

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We examined the effects of physalaemin, an agonist of tachykinin receptors, on mechanical responses in the rat esophagus to clarify possible regulatory roles of tachykinins in esophageal motility. Exogenous application of physalaemin caused tonic contractions in rat esophageal segments when tension was recorded in the longitudinal direction but not when tension was recorded in the circular direction. The physalaemin-evoked contractions were blocked by pretreatment with nifedipine, a blocker of L-type calcium channels in both striated and smooth muscle cells. However, tetrodotoxin, a blocker of voltage-dependent sodium channels in striated muscle cells and neurons, did not affect the physalaemin-induced contractions. These results indicate that physalaemin might induce contractile responses in longitudinal smooth muscle of the muscularis mucosa via direct actions on muscle cells but not on neurons. Although pretreatment with a tachykinin NK1 receptor antagonist, N-acetyl-l-tryptophan 3,5-bis (trifluoromethyl) benzyl ester (L-732,138), did not significantly affect the physalaemin-evoked contractions in rat esophageal segments, a tachykinin NK2 receptor antagonist, (S)-N-methyl-N[4-(4-acetylamino-4-phenylpiperidino)-2-(3,4-dichlorophenyl) butyl] benzamide (SR48968), and a tachykinin NK3 receptor antagonist, (S)-(N)-(1-(3-(1-benzoyl-3-(3,4-dichlorophenyl) piperidin-3-yl)propyl)-4-phenylpiperidin-4-yl)-N-methylacetamide (SR142801), significantly inhibited the physalaemin-evoked contractions. These results suggest that tachykinins can activate longitudinal contraction of smooth muscle in the muscularis mucosa, mediated via tachykinin NK2 and NK3 receptors on muscle cells, in the rat esophagus.

Original languageEnglish
Pages (from-to)202-206
Number of pages5
JournalEuropean Journal of Pharmacology
Volume628
Issue number1-3
DOIs
Publication statusPublished - Feb 25 2010
Externally publishedYes

Keywords

  • (Rat)
  • Esophagus
  • Muscularis mucosa
  • Physalaemin
  • Smooth muscle
  • Tachykinin

ASJC Scopus subject areas

  • Pharmacology

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