Neurally mediated contraction of ileal longitudinal muscle by substance P

Neurosci Lett. 1980 Apr;17(1-2):101-5. doi: 10.1016/0304-3940(80)90069-5.


The time course of the spasmogenic effect of substance P (SP) on the longitudinal muscle (LM) of the guinea-pig ileum was investigated. Maximum effective concentrations of SP (greater than or equal to 10 ng/ml) produced a fast initial response which subsequently declined to about 50% of the initial contraction. This remaining half-maximum contraction was increased by physostigmine and decreased by tropicamide, morphine, and tetrodotoxin; hexamethonium had no effect. The results indicate that SP, apart from its direct action on the LM, also activates cholinergic neurones innervating the LM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cholinergic Fibers / drug effects*
  • Drug Interactions
  • Female
  • Guinea Pigs
  • Ileum / drug effects
  • Ileum / innervation
  • In Vitro Techniques
  • Male
  • Muscle Contraction / drug effects*
  • Muscle, Smooth / drug effects*
  • Neuromuscular Junction / physiology
  • Substance P / administration & dosage
  • Substance P / pharmacology*


  • Substance P