The Effect of Morphine on Motility, Flow and Transit in the Human Ileocolonic Junctional Region

We evaluated the effect of morphine on motility, flow and transit in the distal ileum and ICJ in 8 healthy volunteers who swallowed a multilumen tube (O.D. 8 mm) of 11 side holes. Six closely spaced side holes (intervals 1.5 cm) spanned the ICJ, one distal hole was located in cecum, 4 proximal ports recorded ileal activity. Tubes were located fluoroscopically; maintenance of position was monitored by frequency of rhythmic contractions. Ileal flows were assessed by marker dilution over a 20 cm segment, ileal to cecal transit by injecting lactulose and measuring breath H2. Recordings lasted 5–6 hr fasting, 7–8 hr after drugs and 5–6 hr postprandially (plus drugs); mouth to ileal transit was marked by PEG in meals. A factorial design permitted assessment, double-blinded and randomized, of the actions of morphine sulfate (100 μg/kg i.v.), naloxone (40 pg/kg i.v. plus infusion of 10 μg/kg hrly) and atropine sulfate (7 μg/kg i.v. plus 4 μg/kg hrly).