Peptides do not induce contractions in gastrointestinal smooth muscle in calcium-free solution.
1. Smooth muscle from six sites in the cat gastrointestinal tract was evaluated with respect to its ability to generate contractions in calcium-free solutions. 2. Membrane depolarization and carbachol, but not cholecystokinin or neurotensin, increased tension in smooth muscle segments of esophagus, corpus, duodenum, ileum, proximal colon and distal colon in calcium-free solution. 3. Substance-P produced a contractile response in the absence of calcium but only in the corpus and distal colon. 4. These findings indicate that peptide mediated release of intracellular calcium plays a minimal role in activation of cat gastrointestinal smooth muscle.
Mangel
A W
AW
Department of Medicine, Duke University Medical Center, Durham, NC 27710.
Fitz
J G
JG
Taylor
I L
IL
D000818:Animals; D002118:Calcium / Q000502:physiology*; D002415:Cats; D002766:Cholecystokinin / Q000494:pharmacology; D004064:Digestive System / Q000187:drug effects*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009496:Neurotensin / Q000494:pharmacology; D010277:Parasympathomimetics / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*; D013373:Substance P / Q000494:pharmacology
D010277:Parasympathomimetics; D010455:Peptides; D013373:Substance P; D009496:Neurotensin; D002766:Cholecystokinin; D002118:Calcium