Murine intestinal migrating motor complexes: longitudinal components

• Published in: Neurogastroenterology and motility 2003-06, Vol.15 (3), p.245-256
• Main Authors: Powell, A. K., Bywater, R. A. R.
• Format: Article
• Language: English
• Subjects: Anesthetics, Local - pharmacology; Animals; CMMCs; colon; enteric nervous system; Free Radical Scavengers - pharmacology; Ganglionic Blockers - pharmacology; Gastrointestinal Motility - physiology; Hexamethonium - pharmacology; ileum; Intestines - drug effects; Intestines - physiology; longitudinal muscle; Mice; Morphine - pharmacology; mouse; Muscle Contraction - drug effects; Muscle Contraction - physiology; Muscle, Smooth - drug effects; Muscle, Smooth - physiology; Myoelectric Complex, Migrating - drug effects; Myoelectric Complex, Migrating - physiology; Nifedipine - pharmacology; Nitric Oxide - metabolism; Organ Culture Techniques; Serotonin - pharmacology; Tetrodotoxin - pharmacology; Vasodilator Agents - pharmacology
• ISSN: 1350-1925; 1365-2982
• DOI: 10.1046/j.1365-2982.2003.00405.x

Spontaneous migrating contractions have been described in the circular muscle of the isolated mouse colon and terminal ileum, however, spontaneous events equivalent to these have not been reported in the longitudinal muscle. The longitudinal muscle shortenings in the colon and ileum, which are of similar form, frequency and pharmacology to the circular muscle colonic and ileal migrating motor complexes (CMMCs and IMMCs), are recorded in the present study. The spontaneous ileal and colonic longitudinal muscle shortenings appear to be neurally organized as they are abolished by tetrodotoxin (1 μmol L−1), hexamethonium (500 μmol L−1) and morphine (1 μmol L−1). Endogenously released nitric oxide slowed the frequency of spontaneous ileal and colonic longitudinal muscle shortenings and 5‐hydroxytryptamine increased their frequency. Hyoscine (1 μmol L−1) abolished longitudinal shortenings in the ileum and reduced the amplitude of longitudinal shortening by ∼44% in the colon. Shortenings were effectively abolished by nifedipine (1 μmol L−1). Surgical sectioning of the colon identified that each region of the colon contracted longitudinally in an independent fashion; the distal colon contracted to the greatest amplitude and lowest frequency. The longitudinal preparation is suitable to initially assess the actions of novel pharmacological agents on spontaneous, neurally coordinated, CMMCs and IMMCs in emptied isolated murine intestines.