Digestive motor patterns and transit of luminal contents in canine ileum

Siegle, M. L.; Ehrlein, H. J.

doi:10.1152/ajpgi.1988.254.4.g552

Cited by 29 publications

(16 citation statements)

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“…The relative proportions of these three patterns and the switches between them determine the rate of transport of the contents along the intestine and hence the efficacy of the digestive and absorptive processes [4], [5], [6]. They depend at least in part on the nutrients within the intestinal content [5], [7], [8]. However, the mechanisms by which food and the derived nutrients drive this critical motor function and the underlying neural activity remain ill-defined at best.…”

Section: Introductionmentioning

confidence: 99%

Multiple Neural Oscillators and Muscle Feedback Are Required for the Intestinal Fed State Motor Program

2011

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After a meal, the gastrointestinal tract exhibits a set of behaviours known as the fed state. A major feature of the fed state is a little understood motor pattern known as segmentation, which is essential for digestion and nutrient absorption. Segmentation manifests as rhythmic local constrictions that do not propagate along the intestine. In guinea-pig jejunum in vitro segmentation constrictions occur in short bursts together with other motor patterns in episodes of activity lasting 40–60 s and separated by quiescent episodes lasting 40–200 s. This activity is induced by luminal nutrients and abolished by blocking activity in the enteric nervous system (ENS). We investigated the enteric circuits that regulate segmentation focusing on a central feature of the ENS: a recurrent excitatory network of intrinsic sensory neurons (ISNs) which are characterized by prolonged after-hyperpolarizing potentials (AHPs) following their action potentials. We first examined the effects of depressing AHPs with blockers of the underlying channels (TRAM-34 and clotrimazole) on motor patterns induced in guinea-pig jejunum, in vitro, by luminal decanoic acid. Contractile episode durations increased markedly, but the frequency and number of constrictions within segmenting bursts and quiescent period durations were unaffected. We used these observations to develop a computational model of activity in ISNs, excitatory and inhibitory motor neurons and the muscle. The model predicted that: i) feedback to ISNs from contractions in the circular muscle is required to produce alternating activity and quiescence with the right durations; ii) transmission from ISNs to excitatory motor neurons is via fast excitatory synaptic potentials (EPSPs) and to inhibitory motor neurons via slow EPSPs. We conclude that two rhythm generators regulate segmentation: one drives contractions within segmentation bursts, the other the occurrence of bursts. The latter depends on AHPs in ISNs and feedback to these neurons from contraction of the circular muscle.

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Section: Introductionmentioning

confidence: 99%

Multiple Neural Oscillators and Muscle Feedback Are Required for the Intestinal Fed State Motor Program

2011

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“…Postprandially, the MMC is disrupted by a pattern of irregular contractions that mixes the ingesta with digestive juices and facilitates the exposure of luminal contents to the bowel wall (18) (28). Small intestinal transit, which is slowed postprandially (35), is related to the length of pressure waves (31), indicating that the organization of contractions is an important determinant of luminal flow. More recently, Rayner et al (23) have reported that small intestinal glucose absorption may depend on duodenal motor activity in diabetics (23).…”

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confidence: 99%

Stimulation of small intestinal burst activity in the postprandial state differentially affects lipid and glucose absorption in healthy adult humans

Bryant

Fraser²,

Vozzo³

et al. 2004

American Journal of Physiology-Gastrointestinal and Liver Physi

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Small intestinal motor activity is important for the optimal digestion and absorption of nutrients. These motor responses to feeding are frequently abnormal during critical illness, with the persistence of migrating bursts of contractions during enteral feeding. Whether this disturbance influences nutrient absorption is not known. In this study, the effects of small intestinal burst activity on lipid and glucose absorption were evaluated in 10 healthy human adults (6 males, 4 females, 19–47 yr). Upper gastrointestinal manometry was recorded for 6 h during and shortly after a 20-min intravenous infusion of either erythromycin (1 mg/kg), to stimulate burst activity, or saline (0.9%) in a double-blind randomized fashion. Simultaneously with the start of the intravenous infusion, 60 ml liquid feed mixed with 200 μl 13C-triolein and 2 g 3- O-methylglucose (3-OMG) was infused intraduodenally for 30 min. Absorption of lipid and glucose was assessed using the [13C]triolein breath test and plasma concentrations of 3-OMG, respectively. Infusion of erythromycin was followed by a more rapid onset of burst activity following commencement of the duodenal infusion compared with saline (30 ± 6.1 vs. 58 ± 10.7 min; P < 0.05). Erythromycin was associated with a slower recovery of 13CO2 ( P < 0.01). A positive correlation existed between the time to onset of burst activity and 13CO2 recovery ( P < 0.001). Erythromycin had no effect on 3-OMG absorption. In conclusion, stimulation of small intestinal burst activity reduces the rate of lipid absorption but not glucose absorption in healthy human adults.

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“…Dietary lipids initiate a feedback reflex that converts the propagative to the non-propagative motility pattern that characterizes the fed state [21,22]. Many diverse lipid substances are capable of activating the ileal brake, including triglycerides, phospholipids, and long-and short-chain non-esterified fatty acids (NEFA) [23,24], requiring lipase activity [24].…”

Section: Dietary Fatmentioning

confidence: 99%

Ileal brake: Neuropeptidergic control of intestinal transit

Citters

Lin

2006

Curr Gastroenterol Rep

137

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Digestion and absorption of a meal are time-intensive processes. To optimize digestion and absorption, transit of the meal through the gastrointestinal tract is regulated by a complex integration of neuropeptidergic signals generated as the jejunal brake and ileal brake response to nutrients. Mediators involved in the slowing of transit responses include peptide YY (PYY), chemosensitive afferent neurons, intestinofugal nerves, noradrenergic nerves, myenteric serotonergic neurons, and opioid neurons. The activation of this circuitry modifies the peristaltic reflex to convert the intestinal motility pattern from propagative to segmenting. Fat is the most potent trigger of these transit control mechanisms. The integrated circuitry of gut peptides and neurons involved in transit control in response to nutrients is described in this review.

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Digestive motor patterns and transit of luminal contents in canine ileum

Cited by 29 publications

References 0 publications

Multiple Neural Oscillators and Muscle Feedback Are Required for the Intestinal Fed State Motor Program

Multiple Neural Oscillators and Muscle Feedback Are Required for the Intestinal Fed State Motor Program

Stimulation of small intestinal burst activity in the postprandial state differentially affects lipid and glucose absorption in healthy adult humans

Ileal brake: Neuropeptidergic control of intestinal transit

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