. Spatiotemporal electrical and motility mapping of distension-induced propagating oscillations in the murine small intestine. Am J Physiol Gastrointest Liver Physiol 289: G1043-G1051, 2005. First published August 11, 2005; doi:10.1152/ajpgi.00205.2005.-Since the development of knockout animals, the mouse has become an important model to study gastrointestinal motility. However, little information is available on the electrical and contractile activities induced by distension in the murine small intestine. Spatiotemporal electrical mapping and mechanical recordings were made from isolated intestinal segments from different regions of the murine small intestine during distension. The electrical activity was recorded with 16 extracellular electrodes while motility was assessed simultaneously by tracking the border movements with a digital camera. Distension induced propagating oscillatory contractions in isolated intestinal segments. These propagating contractions were dictated by the underlying propagating slow wave with superimposed spikes. The frequencies, velocities, and direction of the propagating oscillations strongly correlated with the frequencies (r ϭ 0.86), velocities (r ϭ 0.84), and direction (r ϭ 1) of the electrical slow waves. N -nitro-L-arginine methyl ester decreased the maximal diameter of the segment and reduced the peak contraction amplitude of the propagating oscillatory contractions, whereas atropine and verapamil blocked the propagating oscillations. Tetrodotoxin had little effect on the maximal diameter and peak contraction amplitude. In conclusion, distension in the murine small intestine does not initiate peristaltic reflexes but induces a propagating oscillatory motor pattern that is determined by propagating slow waves with superimposed spikes. These spikes are cholinergic and calcium dependent. slow wave; spike; enteric nervous system; small intestine; mice; peristalsis THE SMALL INTESTINE produces a variety of motility patterns to ensure appropriate mixing and propulsion of contents during absorption, digestion, and excretion of food (6, 21). These organized motility patterns are the result of cooperation between smooth muscle cells, interstitial cells of Cajal, and enteric nerves (13). Several patterns of motility have been described such as peristaltic contractions (11, 26), segmental contractions (9, 10), and pendular movements (20,25). Most studies have focused on the peristaltic contractions of the guinea pig small intestine using an in vitro modified Trendelenburg setup (23,27). Only a few studies have investigated other motor patterns (10,25).Since the development of knockout animals, the mouse has become an important model to study gastrointestinal motility. Genetically modified animals offer an additional approach to the pharmacological study of characterizing the receptors involved in the motor function of the gut (1, 3). It is therefore of importance to describe normal murine gastrointestinal motor patterns.In recent years, high-resolution spatiotemporal motility and electr...
