Mechanisms underlying nutrient-induced segmentation within the gut are not well understood. We have shown that @entity27145 and some @entity1522 induce neurally dependent segmentation in @entity840 small intestine in vitro. This study examined the neural mechanisms underlying segmentation in the circular muscle and whether the timing of segmentation @entity2472 also depends on slow waves. @entity27145 (1 mM) was infused into the lumen of @entity840 duodenum and jejunum. Video imaging was used to monitor intestinal diameter as a function of both longitudinal position and time. Circular muscle electrical activity was recorded by using suction electrodes. Recordings from sites of segmenting @entity2472 showed they are always associated with excitatory junction potentials leading to action potentials. Recordings from sites oral and anal to segmenting @entity2472 revealed inhibitory junction potentials that were time locked to those @entity2472 . Slow waves were never observed underlying segmenting @entity2472 . In paralyzed preparations, intracellular recording revealed that slow-wave frequency was highly consistent at 19.5 (SD 1.4) cycles per minute (c/min) in duodenum and 16.6 (SD 1.1) c/min in jejunum. By contrast, the frequencies of segmenting @entity2472 varied widely (duodenum: 3.6-28.8 c/min, median 10.8 c/min; jejunum: 3.0-27.0 c/min, median 7.8 c/min) and sometimes exceeded slow-wave frequencies for that region. Thus nutrient-induced segmentation @entity2472 in @entity840 small intestine do not depend on slow-wave activity. Rather they result from a neural circuit producing rhythmic localized activity in excitatory motor neurons, while simultaneously activating surrounding inhibitory motor neurons.

Mechanisms underlying nutrient-induced segmentation in isolated XXXX small intestine.

@entity1522 :: ('CHEBI:33709', 'Chemical') :: ['amino acids'] @entity2472 :: ('MESH:C536214', 'Disease') :: ['contractions'] @entity27145 :: ('MESH:C031071', 'Chemical') :: ['decanoic acid', 'Decanoic acid'] @entity840 :: ('10141', 'Species') :: ['guinea pig']
@entity840 :: (10141,Species) :: ['guinea pig']
