Motilidad intestinal y microflora / Intestinal motility and microflora

La microflora es el conjunto de colonias microbacterianas que cubren la superficie del tubo digestivo. Cada sujeto humano alberga unos 100 billones de colonias de unas 400 especies distintas, biodiversidad que facilita la vida y el desarrollo del conjunto. La concentración de bacterias va aumentando a lo largo del tubo digestivo, alcanzando concentraciones de 1012 UFC/ml. en el colon. La motilidad del intestino delgado es propulsiva con una fase de barrido que no permite el crecimiento de bacterias. Por el contrario, la motilidad del colon es muy lenta y no propulsiva durante el ayuno y el sueño. Sólo en vigilia y en período postprandial existen ondas de contracción de alta amplitud y rápidamente progresivas en dirección oral-anal. La interacción entre las bacterias presentes en el lumen y las ondas de contracción motora es muy difícil de evaluar. Este efecto se ha estudiado en base a los fármacos que alteran la motilidad y que al aumentar ésta, barren con la flora bacteriana presente. En ese sentido se sabe que el uso de cisaprida acelera el tránsito, reduciendo la densidad de bacterias metanogénicas con un aumento de la excreción de hidrógeno. En cambio, loperamida disminuye el tránsito, aumentando la flora metanogénica (hecho que representa lo que sucede a pacientes constipadas, que tienen flora mayoritariamente productora de metano). Conclusión: La interacción entre motilidad y flora bacteriana es compleja y está poco estudiada fundamentalmente debido a dificultades técnicas.

Microflora is the set of microbacterium colonies covering the digestive tract surface. Each human subject hosts ca. 100 billions of colonies of 400 different species, b23wiodiversity that facilitates life and development of the whole. Bacteria concentration increases throughout the digestive tract, reaching concentrations of 1012 CFU/ml in the colon. Motility of the small intestine is propulsive with a sweeping phase, allowing for the growth of bacteria. On the contrary, motility of the colon is very slow and non-propulsive during fasting and sleeping. Only during wakefulness and postprandial period there are wide-ranging and quickly progressive contraction waves in oral-anal direction. Interaction between bacteria present in lumen and the contraction waves is very hard to assess. This effect has been studied based on drugs that alter motility, and when it increases, they sweep the existing gut flora. In this sense, it is known that the use of cisapride accelerates the transit, reducing the density of methanogenic bacteria with an increase in the hydrogen excretion. On the other hand, loperamide slows down transit, causing an increase of the methanogenic flora (which represents what happens to constipated patients with flora that produces mainly methane). Conclusion: Interaction between motility and gut flora is complex and has not been enough studied mainly due to technical difficulties.

The Effect of Autonomic Nerve System on Neurotensin Induced Motility in Isolated, Vascularly Perfused Rat Colon

BACKGROUND/AIMS: Although neurotensin (NT) stimulates colon motility and the passage of intestinal contents, the associated mechanism of action remains unclear. The objective of this study was to investigate the effects of NT on colon motility using isolated rat colon. METHODS: Intraluminal pressure was measured at both the proximal and distal portions of the isolated colon. An isolated rat colon was perfused with Krebs solution via the superior mesenteric artery. After stabilization, NT was administered in concentrations of 14, 28, 138 and 276 pM. After pretreatment with phentolamine, propranolol, hexamethonium, atropine or tetrodotoxin, NT was administered at a concentration of 276 pM, and then the intraluminal pressure was monitored. RESULTS: NT significantly increased colon motility at concentrations of 14, 28, 138, and 276 in the proximal colon (25.1+/-6.5%, 175.4+/-117.0%, 240.8+/-115.1% and 252.3+/-110.6%, respectively) and in the distal colon (35.6+/-11.8%, 97.5+/-35.1%, 132.7+/-36.7% and 212.1+/-75.2%, respectively). The stimulant effect of NT was more potent in the proximal colon, in a concentration-dependent manner (P<0.05). The stimulant effect of NT was significantly inhibited by atropine at both the proximal and distal colon and by tetrodotoxin at the proximal colon, but not by tetrodotoxin at the distal colon and not by propranolol, phentolamine, or hexamethonium at both the proximal and distal colon. CONCLUSIONS: NT increased colon motility at both the proximal and distal portions of the rat colon. The effects were more prominent at the proximal portion. The results of this study suggest that the stimulant action of NT may be mediated by local cholinergic muscarinic receptors.

The relationship between sigmoid colon propagating motility and cholecystokinin and motilin in patients with irritable bowel syndrome / 中国实用内科杂志

Objective To investigate the relationship between the sigmoid colon propagating contractions and the gut hormones cholecystokinin(CCK)and motilin(MTL)in the patients with irritable bowel syndrome(IBS),and to reveal the gut hormones' modulation to the sigmoid colon motility.Methods Twenty diarrea-predominent IBS patients(D-IBS),and sex/age matched 20 constipation-predominent IBS patients(C-IBS)and 15 healthy volunteers were enrolled in the study.From June 2005 to Mar.2006,the high amplitude propagating waves and loger time of the sigmoid colon was measured by means of a liquid-perfused capillary tube connected to a computer.Meanwhile,the concentrations of CCK,MTL of blood plasma and sigmoid colon mucosa were tested by means of immunoassay technology.Results The D-IBS group had higher amplitude of the sigmoid colon propagating waves and their time percentage than that of the C-IBS group and the control group(P

Changes and Mechanism of Colon Motility of the Rats in Multiple Organ Dysfunction Syndrome Induced by Bacterial Peritonitis / 中国普外基础与临床杂志

Objective To explore the changes of colon motility of the rats in multiple organ dysfunction syndrome (MODS) induced bacterial peritonitis and the effects of IL-6, TNF-? and induce nitricoxide synthase (iNOS) on colon motility. Methods Wistar rats were divided into two groups, which were the control group and the MODS group. The number of stool, the amplitude changes of circular smooth muscle strip, the length of smooth muscle cell, and the changes of serum NO in two groups were observed. The expressions of IL-6, TNF-? and iNOS protein and IL-6 mRNA, TNF-? mRNA and iNOS mRNA in distal colon were investigated by using immunohistochemical methods and RT-PCR. Results The numbers of stool and the amplitude in the MODS group were lower than those of the control group (P

Pre-and post-prandial changes of sigmoid colon motility in patients with irritable bowel syndrome / 中国实用内科杂志

Objective To reveal the changes of pre-and post-prandial sigmoid colon motility in irritable bowel syndrome (IBS) patients and healthy comtrols.Methods Twenty consitipation-predominant and sex/age mathched 20 diarrhea-predominant IBS patients and 15 healthy volunteers were enrolled in the experiment.Migrating long spike bursts,and nonmigrating long spike bursts were recorded by a water perfusing manometry apparatus connected with a computer.Results In fasting status,diarrhea-predominant IBS patients had higher motor index mainly due to the elevated wave amplitude and the percentage of the recording time of the migrating long spike bursts.The test meal significantly increased the amplitude and the number of migrating and nonmigrating long spike bursts in all subjects,especially in the volunteers in the first half hour.The gastrosigmoidocolic reflex of the diarrhea-predominant IBS patients lasted longer than that of the consitipation-predominant IBS patients and healthy controls,mainly due to the increased amplitude of migrating long spike bursts and the number of nonmigrating long spike bursts.Conclusion Diarrhea-predominant IBS patients have stronger sigmoid colon motility in fasting state.The gastrosigmoidocolic reflex appears earlier in healthy subjects than in IBS patients and it lasts longer in diarrhea-predominant IBS patients than in consitipation-predominant IBS patients and healthy controls.