The Posterior Insular Cortex is Necessary for Feeding-Induced Jejunal Myoelectrical Activity in Male Rats.

The gastrointestinal tract exhibits coordinated muscle motility in response to food digestion, which is regulated by the central nervous system through autonomic control. The insular cortex is one of the brain regions that may regulate the muscle motility. In this study, we examined whether, and how, the insular cortex, especially the posterior part, regulates gastrointestinal motility by recording jejunal myoelectrical signals in response to feeding in freely moving male rats. Feeding was found to induce increases in jejunal myoelectrical signal amplitudes. This increase in the jejunal myoelectrical signals was abolished by vagotomy and pharmacological inhibition of the posterior insular cortex. Additionally, feeding induced a decrease and increase in sympathetic and parasympathetic nervous activities, respectively, both of which were eliminated by posterior insular cortical inhibition. These results suggest that the posterior insular cortex regulates jejunal motility in response to feeding by modulating autonomic tone.

Optimization of pacing parameters to entrain slow wave activity in the pig jejunum.

Pacing has been proposed as a therapy to restore function in motility disorders associated with electrical dysrhythmias. The spatial response of bioelectrical activity in the small intestine to pacing is poorly understood due to a lack of high-resolution investigations. This study systematically varied pacing parameters to determine the optimal settings for the spatial entrainment of slow wave activity in the jejunum. An electrode array was developed to allow simultaneous pacing and high-resolution mapping of the small intestine. Pacing parameters including pulse-width (50, 100 ms), pulse-amplitude (2, 4, 8 mA) and pacing electrode orientation (antegrade, retrograde, circumferential) were systematically varied and applied to the jejunum (n = 15 pigs). Pulse-amplitudes of 4 mA (p = 0.012) and 8 mA (p = 0.002) were more effective than 2 mA in achieving spatial entrainment while pulse-widths of 50 ms and 100 ms had comparable effects (p = 0.125). A pulse-width of 100 ms and a pulse-amplitude of 4 mA were determined to be most effective for slow wave entrainment when paced in the antegrade or circumferential direction with a success rate of greater than 75%. These settings can be applied in chronic studies to evaluate the long-term efficacy of pacing, a critical aspect in determining its therapeutic potential.

Resultados de la manometría del cuerpo esofágico y del asa de yeyuno en pacientes operados por cáncer gástrico con gastrectomía total 5 años después de la cirugía / Esophageal manometry in patients with total gastrectomy 5 years after surgery

Resumen Introducción: La técnica de elección para la reconstrucción del tránsito intestinal después de una gastrectomía total es la esófago-yeyuno anastomosis en Y de Roux, la cual evita el reflujo de jugo digestivo alcalino. El objetivo del presente estudio es el de analizar la motilidad del esófago y del asa de yeyuno en pacientes operados con gastrectomía total por cáncer gástrico. Pacientes y método: Se estudió prospectivamente una muestra de 17 pacientes intervenidos mediante gastrectomía total 5 años atrás. En todos ellos se realizaron manometrías esofágicas de alta resolución incluyendo los primeros 7 cm del asa de yeyuno. Resultados: Los resultados de la manometría demostraron motilidad esofágica normal a excepción de la presión máxima intrabolo, la cual se encontraba aumentada en todos los pacientes. La motilidad del asa de yeyuno fue desordenada e inefectiva. Conclusiones: La motilidad del cuerpo esofágico es normal 5 años después de la gastrectomía total. Sin embargo, la presión intrabolo máxima se encuentra aumentada; la causa más probable de este hecho estaría constituida por el asa de yeyuno, que ejerce resistencia al paso del bolo debido a que presenta una actividad motora desordenada y poco propulsiva. El impacto clínico de este hecho es, sin embargo, poco importante.

Abstract Introduction: The most preferred technique to reconstruct the intestinal transit after total gastrectomy for gastric cancer is the Roux-en-Y esophagus-gastrostomy which prevents the reflux of alkaline intestinal juice. The purpose of this study was to analyze the esophageal motility and the motility of the jejunal loop in patients subjected to total gastrectomy. Patients and method: A prospective sample of 17 total gastrectomy patients operated on 5 years before was studied using high resolution esophageal manometry including the first 7 cm of the jejunal loop. Results: Manometry results showed normal esophageal body motility with the exception of the maximum intrabolus pressure that was elevated in all patients. The jejunal loop motility was disordered and ineffective. Conclusions: Esophageal body motility was normal 5 years after the surgical procedure. However, maximum intrabolus pressure was elevated and the most plausible reason would be the jejunal loop that exerts resistance to the bolus passage due to its ineffective motility. However, this fact does not have a significant clinical impact.

ASSESSMENT OF THE GASTRO-JEJUNO-DUODENAL TRANSIT AFTER JEJUNAL POUCH INTERPOSITION / AVALIAÇÃO DO TRÂNSITO GASTROJEJUNODUODENAL APÓS INTERPOSIÇÃO DE ALÇA JEJUNAL

Background : The jejunal pouch interposition between the gastric body and the duodenum after the gastrectomy, although not frequent in the surgical practice today, has been successfully employed for the prevention and treatment of the postgastrectomy syndromes. In the latter, it is included the dumping syndrome, which affects 13-58% of the patients who undergo gastrectomy. Aim : Retrospective assessment of the results of this procedure for the prevention of the dumping syndrome. Methods : Fourty patients were selected and treatetd surgically for peptic ulcer, between 1965 and 1970. Of these, 29 underwent vagotomy, antrectomy, gastrojejunalduodenostomy at the lesser curvature level, and the 11 remaining were submitted to vagotomy, antrectomy, gastrojejunal-duodenostomy at the greater curvature level. The gastro-jejuno-duodenal transit was assessed in the immediate or late postoperative with the contrasted study of the esophagus, stomach and duodenum. The clinical evolution was assessed according to the Visick grade. Results : Of the 40 patients, 28 were followed with the contrast evaluation in the late postoperative. Among those who were followed until the first month (n=22), 20 (90%) had slow gastro-jejuno-duodenal transit and in two (10%) the transit was normal. Among those who were followed after the first month (n=16), three (19%) and 13 (81%) had slow and normal gastric emptying, respectively. None had the contrasted exam compatible with the dumping syndrome. Among the 40 patients, 22 underwent postoperative clinical evaluation. Of these, 19 (86,5%) had excellent and good results (Visick 1 and 2, respectively). Conclusions : The jejunal pouch interposition showed to be a very effective surgical procedure for the prevention of the dumping syndrome in gastrectomized patients.

Racional : A interposição de alça jejunal entre o corpo gástrico e o duodeno após a antrectomia, apesar de pouco frequente na prática cirúrgica atual, tem sido empregada com sucesso na prevenção e tratamento das síndromes pós-gastrectomias. Entre estas se inclui a síndrome de dumping, que acomete 13-58% dos pacientes gastrectomizados. Objetivo : Avaliação retrospectiva dos resultados desse procedimento na prevenção da síndrome de dumping. Métodos : Foram selecionados 40 pacientes todos encaminhados para tratamento cirúrgico de úlcera cloridropéptica entre 1965 e 1970. Destes, 29 foram submetidos à vagotomia, antrectomia, gastrojejunoduodenostomia no nível da pequena curvatura, e os 11 restantes à vagotomia, antrectomia, gastrojejunoduodenostomia no nível da grande curvatura. O trânsito gastrojejunoduodenal foi avaliado no pós-operatório imediato ou tardio por meio do estudo contrastado de esôfago, estômago e duodeno. A evolução clínica no pós-operatório foi avaliada segundo a classificação de Visick. Resultados : Dos 40 pacientes, 28 foram acompanhados com o estudo contrastado no pós-operatório tardio. Entre aqueles de até o 1º mês de pós-operatório (n=22), 20 (90%) apresentaram o trânsito gastrojejunoduodenal lento e dois (10%) tiveram o trânsito normal. Entre os que puderam ser acompanhados após o 1º mês (n=16), três (19%) e 13 (81%) mostraram o esvaziamento gástrico lento e normal, respectivamente. Nenhum apresentou o estudo contrastado compatível com a síndrome de dumping. Entre os 40 doentes, 22 foram submetidos à avaliação clínica pós-operatória. Destes, 19 (86,5%) apresentaram excelentes e bons resultados (Visick 1 e 2, respectivamente). Conclusões : A interposição de alça jejunal mostrou-se procedimento cirúrgico bastante eficaz na prevenção da síndrome de dumping em pacientes gastrectomizados.

Modulatory effects of taurine on jejunal contractility

Taurine (2-aminoethanesulfonic acid) is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM) can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Taurine induced stimulatory effects on the contractility of isolated rat jejunal segments at 3 different low contractile states, and inhibitory effects at 3 different high contractile states. Bidirectional modulation was not observed in the presence of verapamil or tetrodotoxin, suggesting that taurine-induced bidirectional modulation is Ca2+ dependent and requires the presence of the enteric nervous system. The stimulatory effects of taurine on the contractility of isolated jejunal segments was blocked by atropine but not by diphenhydramine or by cimetidine, suggesting that muscarinic-linked activation was involved in the stimulatory effects when isolated jejunal segments were in a low contractile state. The inhibitory effects of taurine on the contractility of isolated jejunal segments were blocked by propranolol and L-NG-nitroarginine but not by phentolamine, suggesting that adrenergic β receptors and a nitric oxide relaxing mechanism were involved when isolated jejunal segments were in high contractile states. No bidirectional effects of taurine on myosin phosphorylation were observed. The contractile states of jejunal segments determine taurine-induced stimulatory or inhibitory effects, which are associated with muscarinic receptors and adrenergic β receptors, and a nitric oxide associated relaxing mechanism.

Effects of the ingestion of 2, 4 Dichlorophenoxyacetic acid on jejunal myenteric neurons in rats

2,4 dichlorophenoxyacetic acid (2,4-D) is a systemic herbicide. The effects of different levels of 2,4-D on some animal organ systems have been examined, but little is known about its role in the enteric nervous system. The purpose of this study was to verify the effects of 2,4-D administration on the density and morphometry of jejunal myenteric neurons in rats. Ten male rats were assigned to control (C) and experimental (E) groups. For 15 days, group E received, via gavage, 5 mg of 2,4-D.kg–1 body weight. On the 16th day, the animals were sacrificed by a lethal dose of thiopental, and the jejunum was removed by laparotomy and used to obtain whole mount preparations for Giemsa staining and NADPH-diaphorase (NADPHd+) histochemistry to identify neurons. The density and cell body area of the myenteric neurons was measured. In the total neuronal population, the neuronal density/mm2 of the jejunum in groups E and C was equivalent, and the cell body area of the rats in group E was lower (p < 0.05) than that of those in group C. For NADPHd+ neurons, the neuronal density did not differ between the groups, although the cell body area was larger (p < 0.05) in group E. It was concluded that even though 2,4-D does not alter the neuronal density in the rat jejunum, it induces cell body atrophy in the general population of neurons and hypertrophy of the NADPHd+ nitric oxide producing neurons without promoting cell death.

Expression of mRNA for glucose transport proteins in jejunum, liver, kidney and skeletal muscle of pigs

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Although pigs are adapted to starch-rich diets and have high turnover rates of glucose, very scarce information is available on the molecular basis of glucose transport. Therefore, the present study attempted a systematic screening for the presence of mRNA of glucose transport proteins in main organs of glucose absorption, production and conservation. From the members of the solute carrier family SLC5A (sodium glucose cotransporter), the porcine jejunum was positive for SGLT1 and SGLT3, but also contained detectable levels of SGLT5. Liver contained SGLT1, SGLT5, traces of SGLT3 and, in one of five pigs, SGLT2. Kidney contained SGLT1, SGLT2, SGLT3, SGLT5 and hardly detectable levels of SGLT4. Skeletal muscle showed weak signals for SGLT3 and SGLT5. Screening for members of the SLC2A family (facilitated glucose transporter) in intestine revealed the presence of mRNA for GLUT1, GLUT2, GLUT5, GLUT7 and GLUT8, while GLUT3, GLUT4, GLUT10 and GLUT11 were also detectable. The liver contained GLUT1, GLUT2 and GLUT8 mRNA, while GLUT3, GLUT4, GLUT5, GLUT10 and GLUT11 were poorly detectable. The kidney was positive for GLUT1, GLUT2, GLUT5, GLUT8 and GLUT11, but traces of GLUT3, GLUT4 and GLUT10 could also be detected. Skeletal muscle had the strongest signal for GLUT4, while GLUT1, GLUT3, GLUT5, GLUT8, GLUT10 and GLUT11 showed weak signals. A total of 12 unique partial cDNA sequences were submitted to GenBank. In conclusion, this study provides molecular insight into the organ-specific expression of glucose transporters in pigs and thus sheds light on the way of glucose handling in this omnivorous species (AU)

Lack of evidence in vivo for nitrergic inhibition by Escherichia coli (STa) enterotoxin of fluid absorption from rat proximal jejunum

Fluid absorption from the proximal jejunum of the anaesthetised rat was measuredin vivo by fluid recovery. As expected, heat stable (STa) enterotoxin fromE.coli reduced fluid absorption. Neither intraperitoneal L-NAME, thought to inhibita putative neurally mediated action of STa, nor similar doses of D-NAME,ameliorated the inhibitory effect on jejunal fluid absorption of STa. Luminally perfused10 mM sodium nitroprusside (SNP) had no effect on fluid absorption whenexpressed per gram dry weight per hour but reduced fluid absorption whenexpressed per cm length per hour. Similarly, 80 but not 40 mg/Kg of L-NAMEreduced fluid absorption when expressed per cm length per hour, while the samedose of D-NAME did not. L-NAME and SNP significantly increased the wet weightto dry weight and the length to dry weight ratio of perfused loops. We conjecturethat smooth muscle relaxation caused by these compounds increases interstitial fluidvolumes that can be misconstrued as changes in absorption when this is expressed percm length or per tissue wet weight. When fluid absorption is expressed per gram dryweight of tissue, there is no evidence for a role of nitric oxide in normal or STa inhibitedfluid absorption (AU)

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Lack of evidence in vivo for nitrergic inhibitionby Escherichia coli (STa) enterotoxin of fluidabsorption from rat proximal jejunum

Fluid absorption from the proximal jejunum of the anaesthetised rat was measuredin vivo by fluid recovery. As expected, heat stable (STa) enterotoxin fromE.coli reduced fluid absorption. Neither intraperitoneal L-NAME, thought to inhibita putative neurally mediated action of STa, nor similar doses of D-NAME,ameliorated the inhibitory effect on jejunal fluid absorption of STa. Luminally perfused10 mM sodium nitroprusside (SNP) had no effect on fluid absorption whenexpressed per gram dry weight per hour but reduced fluid absorption whenexpressed per cm length per hour. Similarly, 80 but not 40 mg/Kg of L-NAMEreduced fluid absorption when expressed per cm length per hour, while the samedose of D-NAME did not. L-NAME and SNP significantly increased the wet weightto dry weight and the length to dry weight ratio of perfused loops. We conjecturethat smooth muscle relaxation caused by these compounds increases interstitial fluidvolumes that can be misconstrued as changes in absorption when this is expressed percm length or per tissue wet weight. When fluid absorption is expressed per gram dryweight of tissue, there is no evidence for a role of nitric oxide in normal or STa inhibitedfluid absorption (AU)

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Morphological and quantitative analyses of the NADH-d myenteric neurons of the jejunum of rats submitted to experimental chronic alcoholism / Análisis Morfológico y Cuantitativo de de Neuronas Mientéricas NADH-d del Yeyuno de Ratas Sometidas a Alcoholismo Crónico Experimental

El objetivo del trabajo fue verificar, durante un período experimental de 210 días, los posibles efectos del etanol sobre la morfología y densidad de las neuronas mientéricas NADH-diaforasa, en el yeyuno de ratas alcohólicas. Utilizamos 10 animales (Rattus norvegicus) separadas en dos grupos: el control (n=5) que recibió una dieta proteica normal (22 por ciento) y agua ad libitum; el otro, alcohólico, que recibió dieta proteica normal NUVILAB (22 por ciento) y brandy de azúcar de caña diluido a 30 Gay Lussac (30 v/v). El segmento de yeyuno fue obtenido y sometido a técnicas histoquímicas para teñir las células nerviosas. La observación a través de microscopía de luz mostró que no hubo diferencias morfológicas de importancia entre las neuronas del grupo control y el sometido a alcoholismo. El recuento neuronal en el grupo control, llevado a cabo en 40 campos microscópicos (8,96 µm2), de las regiones mesentérica y antimesentérica, determinó 1.131 y 693 neuronas, respectivamente, mientras que en el grupo alcohólico se encontraron 1.229 y 860 neuronas, respectivamente. El incremento significativo en el número de neuronas en la región mesentérica, en el grupo de las ratas alcohólicas, es debido a un crecimiento físico menor de esos animales comparados con el grupo control. El etanol causó malnutrición y consecuentemente, las ratas alcohólicas mostraron una densidad neuronal más amplia debido a una dispersión menor.

The objective of our work was to verify, during an experimental period of 210 days, the possible effects of the ethanol on the morphology and density of the NADH-diaforase myenteric neurons in the jejunum of alcoholic rats. We used 10 animals (Rattus norvegicus) separated in 2 groups: the controls (n=5), that received a normal proteic diet (22%) and water ad libitum; the alcoholic, that received NUVILAB normal proteic chow (22%) and sugar cane brandy diluted at 30 Gay Lussac (30 v/v). The jejunum segment was collected and submitted to the histochemical technique to stain the nervous cells and, then, to the elaboration of membrane whole mounts. The observation through light microscopy showed that there are no expressive morphologic differences between the ganglia of neurons of the control and alcoholic rats. The counting of neurons, carried out in 40 microscopic fields (8.96µm2) in the control group, at the mesenteric and antimesenteric regions, found 1,131 and 693 neurons respectively, while, the alcoholic group found 1,229 and 860 neurons. The significant increase in the number of neurons in the mesenteric region, in the alcoholic rats, is due to the smaller physical growth of those animals when compared to the controls. The ethanol caused malnutrition and consequently the alcoholic rats showed a larger neuronal density due to its smaller dispersion.

Cell proliferation and migration in the jejunum of suckling rats submitted to progressive fasting

Cell proliferation and migration in the intestinal crypts, and cell migration in the villus are controlled by different mechanisms in adult rats. In the present study, weanling rats and fasting rats were used to quantitatively study the correlation of cell cycle parameters and epithelial cell migration in crypts and intestinal villi. Eighteen-day-old rats received a single injection of tritiated thymidine[3H]T dR (23:00 h); half of the pups were submitted to fasting 5 h earlier. Cell proliferation was determined in radioautographs of jejunal crypts, on the basis of the labeling indices (LI) taken 1,8,13 and 19 h after [3H]TdR. The results showed that the labeling index did not differ 1 h or 19 h after [3H]TdR between the fed (38.7 percent or 48 percent) and fasting groups (34.6 percent or 50.4 percent). The modified method of grain count halving indicated that cell cycle time did not differ between fed (16.5 h) and fasting rats (17.8 h); the growth fraction, however, had lower values in fasting (59 percent) than in fed rats (77 percent). Cell migration in the crypt, estimated by the LI obtained for each cell position, did not change with treatment. As for the villi, the cell migration rate was significantly retarded by 3 cell positions (8 percent). These results suggest that the cell migration in the villi of weanling pups does not depend directly on the cell proliferation and migration in the intestinal crypt, but is directly affected by the absence of food in the lumen.

Estudo dos movimentos espontâneos e sob efeitos farmacológicos de segmentos isolados da junçäo duodeno-jejunal de rato / Spontaneous and drug-induced movements of isolated segments of the duodenojejunal junction of rat

Estudou-se, "in vitro", a motilidade espontânea e sob efeito farmacológico da junçäo duodenojejunal de ratos. Tomou-se três segmentos: pré, no nível e após a junçäo. Os registros foram feitos em quimógrafo com papel enfumaçado. A acetilcolina e fisostigmina diminuíram as amplitudes de contraçöes nos três segmentos, bem como a noradrenalina e procaína. A freqüência das contraçöes espontâneas apresentou um gradiente decrescente no sentido crânio-caudal, observado tambem sob o efeito da noradrenalina. Sob o efeito acetilcolina e fisostigmina elas se igualaram. Näo houve diferença quanto ao tipo de ondas (I, II e III), sendo mais frequüente a onda I. Elas näo se alteraram sob a açäo da acetilcolina e noradrenalina, e a fisostigmina alterou as características das ondas. O efeito da procaína sobre as ondas foi marcante, diferenciando, nitidamente, o segmento pré da transiçäo duodenojejunal. O tono foi igual nos três segmentos. A acetilcolina diferenciou o segmento pré do pós-junçäo duodenopejunal. A noradrenalina e a procaina diminuiram o tono e a fisostigmina aumentou-o igualmente nos três segmentos