In vitro analysis of rat intestinal wall movements at rest and during propagated contraction: a new method.

Intestinal wall motions are not easily studied and are frequently deduced from manometric and electromyographic measurements. This study aimed to establish a method of wall movement analysis based on an automatic technique of image processing. Segments of rat jejunum were fixed in an organ bath under isometric conditions. A real-time edge-detection algorithm was used to find the contours of the intestine using video imaging. After the measurement, a mapping of intestinal wall movements was performed based on diameter variations. In the 260 experiments without stimulation, intestinal wall activity was always detected. Propagated activity was found in 40% of the experiments and periodic wall motion in 60%, with 0.5-Hz activity found more frequently (41%) than 0.24-Hz activity (19%). These cyclic activities, related to intestinal slow waves, had their amplitude decreased by acetylcholine and were modified by vapreotide. Analysis of a propagated wave after cholinergic stimulation showed that it is characterized by an increase of the diameter of the intestine followed by a decrease. Moreover, this methodology allows analysis of the initiation of a propagated wave.