Advertisement

Evidence for a Muscarinic Inhibitory Brake Activated by Peptides in the Canine Small Intestine

  • J. E. T. Fox
  • E. E. Daniel
  • T. J. MacDonald
  • J. Jury
  • K. H. Robotham

Abstract

Acetylcholine (ACH) injected intraarterially (ia) contracts the canine gut by a tetrodotoxin-(TTX) and hexamethonium-insensitive, atropine-sensitive mechanism. Field stimulation (40V, 0.5ms, 1–5Hz) produces phasic and tonic contractions which are slightly reduced by hexamethonium, almost eliminated by atropine (1) and blocked by TTX. Thus the major endogenous stimulant released by field stimulation is ACH which stimulates activity via a muscarinic receptor on the smooth muscle. Phasic and tonic contractions can be elicited after atropine by ia motilin and appear to represent release of a non-muscarinic transmitter to the smooth muscle (2).

Keywords

Muscarinic Receptor Gastrointestinal Motility Myenteric Plexus Field Stimulation Excitatory Response 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Fox, J.E.T., Daniel, E.E., Jury, J., Track, N.S. and Chiu, S. (1983). Cholinergic control mechanisms for immunoreactive motilin release and motility in the canine duodenum. Can. J. Physiol. (in press)Google Scholar
  2. 2.
    Fox, J.E.T., Daniel, E.E., Jury, J., and Robotham, H. (1983). The mechanism of motilin excitation of the canine small intestine. Life Sci. (submitted)Google Scholar
  3. 3.
    Daniel, E.E., Gonda, T., Domoto, T., Oki, M. and Yanaihara, N. (1982). The effects of substance P and met-enkephalin in dog ileum Can. J. Physiol. Pharmacol., 60, 830–840PubMedCrossRefGoogle Scholar
  4. 4.
    Sawynok, J. and Jhamandas, K. (1977). Muscarinic feedback inhibition of acetylcholine release from the myenteric plexus in the guinea pig ileum and its status after chronic exposure to morphine. Can. J. Physiol. Pharmacol., 55, 909–916PubMedCrossRefGoogle Scholar
  5. 5.
    Szerb, J.C. (1980). Effects of low calcium and of oxytremosine on the kinetics of the evoked release of 3H acetylcholine from the guinea pig myenteric plexus: comparison with morphine. Naunyn Schmiedebergs Arch Pharmac., 311, 119–127CrossRefGoogle Scholar
  6. 6.
    Morita, K., North, R.A. and Tokimasa, T. (1982). Muscarinic presynaptic inhibition of synaptic transmission in myenteric plexus of guinea pig ileum. J. Physiol., 333, 141–149PubMedGoogle Scholar
  7. 7.
    Hammer, R., Berrie, C.P., Bridsall, N.J.M., Burgen, A.S.V. and Hulme, E.C. (1980). Pirenzipine distinguishes between different subclasses of muscarinic receptors. Nature, 283, 90–92PubMedCrossRefGoogle Scholar
  8. 8.
    Goyal, R.K. and Rattan, S. (1975). Nature of the vagal inhibitory innervation to the lower esophageal sphincter. J. Clin. Invest., 55, 1119–1126PubMedCrossRefGoogle Scholar
  9. 9.
    Oki, M., and Daniel, E.E. (1980). Distribution of substance P like immunoreactivity in both intrinsic and extrinsic nerves of the gastrointestinal tract. Nippon Heikatonkin Gakkai Zasshi, 16, 75–77Google Scholar
  10. 10.
    Daniel, E.E., Sakai, Y., Jury, J. and Fox, J.E.T. (1982). Mode of action of neurotensin on gastrointestinal motility. In: Wienbeck, M. (ed). Motility of the Digestive Tract. pp. 87–93. ( N.Y.: Raven Press )Google Scholar
  11. 11.
    Krier, J., and Szurszewski, J.H. (1983). Effect of substance P on colonic mechanoreceptors motility and sympathetic neurones. Am. J. Physiol., G259 - G267Google Scholar
  12. 12.
    Hammer, R. (1980). Muscarinic receptors in the stomach. Scand. J. Gastroenterol., 15: Suppl. 66, 5–11Google Scholar

Copyright information

© MTP Press Limited 1984

Authors and Affiliations

  • J. E. T. Fox
  • E. E. Daniel
  • T. J. MacDonald
  • J. Jury
  • K. H. Robotham

There are no affiliations available

Personalised recommendations