Evidence that axons containing substance P in the guinea-pig ileum are of intrinsic origin

R. Franco, M. Costa, J. B. Furness

    Research output: Contribution to journalArticle

    75 Citations (Scopus)

    Abstract

    Acid extracts from both normal and extrinsically denervated ileum contained a compound which was indistinguishable from synthetic substance P; this compound was assayed by examining its contractile effect on the longitudinal muscle of segments of ileum in which receptors for acetylcholine and histamine were blocked. Contractions caused by the compound were markedly and selectively antagonized when the ileum was made insensitive to the action of substance P. The activities in the extract and of synthetic substance P were both destroyed by chymotrypsin but were not affected by trypsin or carboxypeptidase B. The concentrations of substance P-like material in normal and extrinsically denervated segments were not significantly different, being equivalent to 0.48 μg of substance P per g of external muscle plus myenteric plexus. A compound with substance P-like activity was liberated by stimulation of intramural nerves, either electrically or by dimethylphenylpiperazinium, in both normal and extrinsically denervated segments of ileum. The release of this compound was prevented by tetrodotoxin and its action on the muscle was blocked when the ileum was made insensitive to the action of substance P. Experiments with transmural stimulation showed that excitatory nerve pathways involving substance P neurons extend for less than 4 cm along the intestine.

    Original languageEnglish
    Pages (from-to)57-63
    Number of pages7
    JournalNaunyn-Schmiedeberg's Archives of Pharmacology
    Volume307
    Issue number1
    DOIs
    Publication statusPublished - 1 May 1979

    Keywords

    • Autonomic nervous system
    • Intestine
    • Peptidergic nerves
    • Substance P

    Fingerprint Dive into the research topics of 'Evidence that axons containing substance P in the guinea-pig ileum are of intrinsic origin'. Together they form a unique fingerprint.

  • Cite this