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Per M. Hellström - One of the best experts on this subject based on the ideXlab platform.
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Neuropeptide Y Inhibits the Migrating Myoelectric Complex and Delays Small Intestinal Transit in Rats
Neurogastroenterology & Motility, 2008Co-Authors: Per M. Hellström, C. JohanssonAbstract:The effect of neuropeptide Y (NPY) on Myoelectric activity of the small intestine was related to transit of a radioactive marker in fasted conscious rats. Myoelectric activity was recorded with bipolar electrodes implanted 5, 20, and 35 em distal to pylorus. A radioactive marker was administered luminally in the duodenum immediately after an activity front of a Migrating Myoelectric Complex (MMC) had passed the first recording site. Intravenous infusion of NPY (50–100 pmol kg−1 min −1) did not affect the MMC in the duodenum but interrupted its distal propagation and inhibited spiking in the jejunum. At higher doses, NPY (200–800 pmol kg−1 min−1) abolished the MMC at all recording sites. Effects of NPY on Myoelectric activity were not prevented by guanethidine, phentolamine, propranolol, or naloxone. The effects of NPY on Myoelectric activity corresponded to a dose-related slowing of transit of the marker. In controls, the peak of the marker was propagated ahead of the activity front over the three recording sites. NPY (100 pmol kg−1 min−1) slowed transit, with the peak of the marker proximal to the third electrode site. NPY (400 pmol kg−1 min−1) further delayed transit, with the peak of the marker proximal to the second electrode site. We conclude that the activity front of the MMC exerts a high propulsive capacity. NPY produced a dose-related nonadrenergic inhibition of the intestinal Myoelectric activity, which may account for a delayed transit of intestinal contents.
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Activity Fronts of Migrating Myoelectric Complex: Initiation by Luminal Bile Acids in Rat Small Intestine
Neurogastroenterology & Motility, 2008Co-Authors: I. Nilsson, T. Svenberg, B. Wallin, G. Hedenborg, Per M. HellströmAbstract:The aim of the present study was to investigate the possible role of bile in regulation of fasting small intestinal motility in the rat. Myoelectric activity was recorded by bipolar electrodes implanted in the jejunum, 15, 25, and 35 cm distal to the pylorus. After recording Migrating Myoelectric Complexes (MMCs), total biliary drainage was performed by cannulating the bile duct of 15 rats. After biliary drainage for 267 (222–312) minutes (mean and 95% confidence interval), a characteristic continuous irregular spiking activity appeared at all recording sites. When continuous irregular spiking had persisted for 2 hours, a mixture of 20 mM taurocholic and 10 mM taurochenodeoxycholic acid was infused into the duodenum (0.5 μ/mol/min for 90 min) of seven rats. Bile acid infusion induced three to six activity fronts within 25 to 47 minutes in all animals. Maximal bile acid secretion in response to bile acid infusion was obtained about 1 hour after the last induced activity front, when the motility pattern had returned to irregular spiking. In eight rats with biliary drainage but without bile acid infusion, irregular spiking activity persisted for at least 10 hours. In sham-operated rats, regular activity fronts started after 221 (146–296) minutes. Thus drainage of bile changes the motility pattern from MMC to continuous irregular spiking, while duodenal bile acid infusion after biliary drainage reinstates the MMC pattern in rat small intestine.
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physiological regulation and no dependent inhibition of Migrating Myoelectric Complex in the rat small bowel by oxa
American Journal of Physiology-gastrointestinal and Liver Physiology, 2003Co-Authors: Marcus Ehrstrom, E Naslund, Annette L Kirchgessner, Per M. HellströmAbstract:Orexin A (OXA)-positive neurons are found in the lateral hypothalamic area and the enteric nervous system. The aim of this study was to investigate the mechanism of OXA action on small bowel motili...
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Regulatory role of 5-HT and muscarinic receptor antagonists on the Migrating Myoelectric Complex in rats.
European journal of pharmacology, 2003Co-Authors: Lars Göran Axelsson, Berndt Wallin, Per Göran Gillberg, Birger Sjöberg, Charlotte Söderberg, Per M. HellströmAbstract:The 5-HT(3) and 5-HT(4) receptor antagonists alosetron and piboserod, and the muscarinic receptor antagonists PNU-171990A (2-(diisopropylamino)ethyl 1-phenylcyclopentanecarboxylate, hydrochloride) and PNU-174708A (2-(diisopropylamino)ethyl 1-phenylcyclohexanecarboxylate) were studied by electromyography, defining the Migrating Myoelectric Complex (MMC) after i.v. administration in conscious rats. Alosetron prolonged the MMC cycle length from 16.6 to maximally 30.4 min at the dose 0.5 mg kg(-1). Piboserod promptly abolished MMC pattern and prolonged cycle length from 16.5 to >60 min at 0.5 mg kg(-1). PNU-171990A and PNU-174708A had no effect on basal cycle length up to a dose of 20 mg kg(-1). In controls, saline did not change the MMC pattern, while L-hyoscyamine at the same dose, 20 mg kg(-1), prolonged cycle length from 17.6 to 29.0 min. None of the drugs affected duration or propagation velocity of phase III of MMC. Blockade of 5-HT(4) receptors seems to exert a powerful inhibitory effect on motility, 5-HT(3) receptor blockade is less efficient and muscarinic receptor blockade has low efficacy.
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serotonin stimulates Migrating Myoelectric Complex via 5 ht3 receptors dependent on cholinergic pathways in rat small intestine
Neurogastroenterology and Motility, 1999Co-Authors: Mikael Lordal, Per M. HellströmAbstract:We have investigated the effect of 5-hydroxytryptamine (5-HT) and different 5-HT-receptor antagonists and atropine on the Migrating Myoelectric Complex in the rat small intestine. Infusion of 5-HT dose-dependently shortened the interval between phase III of the Migrating Myoelectric Complex (MMC). In untreated animals the interval in upper jejunum was 19.1 (16.0–22.1) min. At doses of 10 and 20 nmol kg–1 min–1, the interval decreased to 15.2 (12.0–18.4) and 10.2 (9.4–11.0) min, respectively. The 5-HT3-receptor antagonist ondansetron (0.5 mg kg–1) alone increased the MMC interval from 20.8 (15.1–26.5) to 33.9 (19.4–48.4) min. Neither methiothepin (0.5 mg kg–1) nor ketanserin (0.5 mg kg–1), selective for 5-HT15-HT2-and 5-HT2-receptors, respectively, changed the MMC interval. The 5-HT4-receptor antagonist GR 113808 (0.5 mg kg–1) disrupted the MMC and induced irregular spiking activity. Ondansetron and atropine antagonized the 5-HT-induced shortening of the MMC interval. Neither methiothepin nor ketanserin affected the response to 5-HT. GR 113808 did not block the response to 5-HT in half of the animals; however, in the remaining ones MMC was disrupted and irregular spiking induced. In conclusion, these results show that 5-HT dose-dependently stimulates the cycling of the MMC in the small intestine via 5-HT3-receptors and a cholinergic final pathway. Our findings encourage further studies on the role of the 5-HT3-receptor in the control of gastrointestinal motility.
Gaston Vantrappen - One of the best experts on this subject based on the ideXlab platform.
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Relation between slow-wave frequency and spiking activity during the Migrating Myoelectric Complex in dogs.
Pflugers Archiv : European journal of physiology, 1992Co-Authors: W Janssens, P Caenepeel, Jozef Janssens, H Vandenbogaerde, Gaston VantrappenAbstract:The quantitative relation between slow-wave periods and spiking activity was evaluated in vivo in canine small intestine during the fasted state. Experiments were performed in three conscious dogs with three bipolar electrodes, implanted respectively 10, 25 and 40cm beyond the ligament of Treitz. Digitized electrical recordings were automatically processed for the individual slow-wave periods and spike-burst intensities using a set of computer programs developed in our laboratory. A linear correlation existed between the degree of spiking activity and the average length of the preceding slow-wave period. The slopes of the regression lines were less steep for more distal electrodes. A second series of experiments showed that an increase in the slow-wave period precedes the onset of phase 3 of the Migrating Myoelectric Complex and that a fall in slow-wave period precedes the end of phase 3. These data show that a low slow-wave frequency is accompanied by a facilitation of spiking activity, whereas shortening of the slow-wave period is accompanied by a decrease in spike burst intensity. This relation between slow-wave period and spiking activity shows an aboral trend that may be related to intrinsic slow-wave frequency.
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Variation of slow-wave frequency and locking during the Migrating Myoelectric Complex in dogs.
American Journal of Physiology-Gastrointestinal and Liver Physiology, 1991Co-Authors: P Caenepeel, Gaston Vantrappen, Jozef Janssens, W Janssens, A Accarino, Hendrik EyssenAbstract:Slow waves determine rhythm and polarity of spike bursts. We measured the variation of slow-wave frequency (swf) and locking (swl) in the canine jejunum during the various phases of the Migrating Myoelectric Complex (MMC) and during induced phase III (erythromycin 125 micrograms/kg iv bolus or somatostatin 2.5 micrograms.kg-1.h-1 iv infusion), blocked phase III (atropine 20 micrograms/kg iv bolus), and so-called stationary phase III activity (cisapride 150 micrograms/kg iv bolus). The EMG of 4 dogs, implanted with 10 bipolar electrodes, was recorded on a polygraph. Our results indicate that swf and swl change during the MMC from a stepwise swf gradient with slow waves locked in plateaus during phase I to a continuous swf gradient without or with significantly reduced phase locking during phase III. The length of the first swf plateau decreases significantly from 42 +/- 12 cm post Treitz during phase I to 11 +/- 4 cm during spontaneous phase III. Atropine block of phase III activity prevents phase unlocking and development of a continuous swf gradient. Our hypothesis is that phase unlocking may be one of the induction mechanisms of spike-burst activity.
Alex Bortoff - One of the best experts on this subject based on the ideXlab platform.
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Migrating Myoelectric Complex and jejunal slow-wave propagation after Roux gastrectomy in dogs
Digestive Diseases and Sciences, 1993Co-Authors: Alan Woodward, Lelan F. Sillin, Alex BortoffAbstract:Roux-en-Y gastrectomy is associated with a high incidence of symptoms of gastric stasis. Retrograde propagation of jejunal electrical slow waves and spike bursts has been implicated in the Roux Y stasis syndrome. Since the fasted state may persist after feeding, this study examined the extent of retrograde slow-wave propagation in the fasted state, particularly during aboral migration of phase III. Six dogs underwent Roux gastrectomy and placement of bipolar electrodes along the Roux limb. Four normal dogs with electrodes acted as controls. Thirty-five Migrating Myoelectric Complexes were recorded in Roux dogs and 13 in controls. In Roux dogs, the incidences of retrograde propagation of slow waves during the Migrating Myoelectric Complex were phase I 56±13%, phase II 60±12% and phase III 58±14% (not significant). For controls, the incidences were 0%, 0%, and 1%, respectively ( P
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Migrating Myoelectric Complex and jejunal slow wave propagation after roux gastrectomy in dogs
Digestive Diseases and Sciences, 1993Co-Authors: Alan A Woodward, Lelan F. Sillin, Alex BortoffAbstract:Roux-en-Y gastrectomy is associated with a high incidence of symptoms of gastric stasis. Retrograde propagation of jejunal electrical slow waves and spike bursts has been implicated in the Roux Y stasis syndrome. Since the fasted state may persist after feeding, this study examined the extent of retrograde slow-wave propagation in the fasted state, particularly during aboral migration of phase III. Six dogs underwent Roux gastrectomy and placement of bipolar electrodes along the Roux limb. Four normal dogs with electrodes acted as controls. Thirty-five Migrating Myoelectric Complexes were recorded in Roux dogs and 13 in controls. In Roux dogs, the incidences of retrograde propagation of slow waves during the Migrating Myoelectric Complex were phase I 56±13%, phase II 60±12% and phase III 58±14% (not significant). For controls, the incidences were 0%, 0%, and 1%, respectively (P<0.006 versus Roux dogs). In the Roux limb, retrograde propagation of slow waves, and hence spike bursts, occurs even during aboral migration of phase III. This abnormality may contribute to the Roux Y stasis syndrome.
Romuald Zabielski - One of the best experts on this subject based on the ideXlab platform.
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Zinc output in pancreatic juice in preruminant calves - a preliminary study
1999Co-Authors: Mikolaj A. Gralak, Violetta Naughton, A. Bogucka-sciezynska, Romuald ZabielskiAbstract:Mean zinc concentration in pancreatic juice was 10.39 +/- 4.67 mg/l (median - 9.33). It varied much from 2.8 to 20.55 mg/l (coefficient of variation - 45%). It varied independently on the phase of Migrating Myoelectric Complex (MMC). Pancreatic zinc output varied even more: from 1.26 to 52.79 mu g/5 minutes (mean - 11.39) and the variation (coefficient of variation - 98%) was in phase with the Migrating Myoelectrical Complex (MMC). Estimated mean total pancreatic zinc output in preruminant calves is 3.28 mg/day (2.26 to 3.42 mg/day).
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Periodic fluctuations of gut regulatory peptides in phase with the duodenal Migrating Myoelectric Complex in preruminant calves: effect of different sources of dietary protein
The British journal of nutrition, 1998Co-Authors: Romuald Zabielski, Claude Dardillat, Isabelle Le Huërou-luron, Christine Bernard, Jean Alain Chayvialle, Paul GuilloteauAbstract:Four preruminant calves with implanted electrodes in the duodenum and a catheter in the external jugular vein were used for investigation of plasma gut regulatory peptide profiles during different phases of Migrating Myoelectric Complex (MMC) in the small intestine. The effects of different dietary proteins on the rhythmic activity of gut peptides and gastrointestinal motility were compared. In particular, the effects of skimmed-milk protein (retaining physiological patterns of abomasal clotting, and abomaso-intestinal digesta flow) v. fish protein (devoid of clotting activity and modifying the digesta flow) were studied. In calves fed on the milk diet, plasma concentrations of pancreatic polypeptide, motilin, secretin, cholecystokinin (CCK) and somatostatin, but not vasoactive intestinal polypeptide or gastrin, fluctuated in phase with the duodenal MMC in the preprandial period. Feeding transiently affected the intestinal MMC and abolished the peptide fluctuations in a specimen-specific manner. In contrast, calves fed on the fish-protein diet showed more profound changes in intestinal MMC. In these animals the MMC-related fluctuations were significant only for plasma CCK. In conclusion, the source of dietary protein has an impact on the physiological endocrine function of the small intestine. Observed fluctuations of plasma gut regulatory peptides seem to be secondary to duodenal motility cycles.
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Kinetics of pancreatic juice secretion in relation to duodenal Migrating Myoelectric Complex in preruminant and ruminant calves fed twice daily
The British journal of nutrition, 1997Co-Authors: Romuald Zabielski, Pawel R. Kiela, Violetta Leśniewska, Ryszard Krzemiński, Marioletta Mikołajczyk, W. BarejAbstract:Daily secretion of pancreatic juice, including postprandial responses to food, was investigated in two groups of calves: preruminant (fed with liquid food) and ruminant (fed with solid food). Male Friesian calves (1 week old and 6 weeks old) were surgically fitted with a pancreatic duct catheter, duodenal cannula and two duodenal electrodes. Continuous 24 h collections of pancreatic juice and Myoelectrical recordings were performed with minimal restraint and disturbance of animals. In both groups of calves clear periodic fluctuations in pancreatic juice secretion (volume, protein output and trypsin activity) coinciding with duodenal Migrating Myoelectric Complexes (MMC) were recorded. Secretion of juice per cycle and per day was greater in ruminant calves, but the frequency and amplitude of cycles were lower in this group. There were no differences between day and night-time preprandial pancreatic cycles and duodenal MMC in preruminant calves, whilst in ruminant calves, evening MMC were longer than morning MMC. The pancreatic cephalic phase (increase of volume flow, protein output and trypsin activity during and just after food intake) was significant only in preruminant calves following morning feeding. Postprandial pancreatic cycles did not differ from preprandial cycles, except the pancreatic cycle (juice volume and trypsin activity) in which food was offered in preruminant calves. No gastric or intestinal phase was observed in either group of calves. In conclusion, biological cycles of the gastrointestinal tract are present in both preruminant and ruminant calves, and these cycles evolve along with the change from liquid to solid food.
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Intraduodenal cholecystokinin octapeptide (CCK-8) can stimulate pancreatic secretion in the calf
International Journal of Pancreatology, 1995Co-Authors: Romuald Zabielski, Takenori Onaga, Seiyu Kato, Hitoshi Mineo, Stefan G. PierzynowskiAbstract:The effect of CCK-8 administered into the duodenal lumen and into the systemic blood on pancreatic, secretion and duodenal Migrating Myoelectric Complex (MMC) was studied in four calves. Simultaneous MMC recordings and collections of pancreatic juice were performed on valves that had been fasted overnight. Intraduodenal (o, 100, and 300 pmol/kg body wt) and intravenous (0, 30, and 100/pmol kg) infusions of CCK-8 were made for 5 min during the no spiking activity (NSA) phase of duodenal MMC associated with a nadir of periodic pancreatic secretion. CCK-8 was also administered during continuous atropine infusion (5 μg/kg/min). Both intraduodenal and intravenous infusions of CCK-8 resulted in marked pancreatic responses in juice outflow, bicarbonate output, and protein output. Atropine decreased pancreatic response (protein output) to intravenous CCK-8 and markedly inhibited the response (juice flow, bicarbonate, and protein output) to intraduodenal CCK-8. Infusions of CCK-8 did not affect the duration of MMC in the duodenum. Plasma CCK increased significantly after intravenous infusion, but remained unchanged after intraduodenal infusion. In conclusion, CCK-8 can stimulate pancreatic secretion from the duodenal lumen, possibly via a cholinergic mechanism in the calf.
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Plasma secretin fluctuates in phase with periodic pancreatic secretion and the duodenal Migrating Myoelectric Complex in calves.
Research in veterinary science, 1994Co-Authors: Romuald Zabielski, Y. Terui, Takenori Onaga, H. Mineo, Seiyu KatoAbstract:Abstract Plasma secretin and cholecystokinin ( CCK ) levels and the periodic secretions of the exocrine pancreas were studied simultaneously with the duodenal Migrating Myoelectric Complexes ( mmc ) in six milk-fed calves which had been starved overnight. The experiments were performed first when the calves were 10 to 16 days old and subsequently when they were 36 to 45 days old. Plasma secretin and the secretion of pancreatic juice fluctuated periodically in phase with the duodenal MMC : plasma secretin, and the pancreatic secretion of water and protein were significantly higher during the phase of irregular spiking activity than during the phase of no spiking activity in both investigations. Plasma CCK did not change throughout the MMC . The intravenous infusion of secretin at 120 pmol kg −1 bodyweight for one hour markedly stimulated pancreatic secretion and prolonged the duodenal MMC cycle, but it did not abolish pancreatic and duodenal periodic activity.
W Janssens - One of the best experts on this subject based on the ideXlab platform.
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Relation between slow-wave frequency and spiking activity during the Migrating Myoelectric Complex in dogs.
Pflugers Archiv : European journal of physiology, 1992Co-Authors: W Janssens, P Caenepeel, Jozef Janssens, H Vandenbogaerde, Gaston VantrappenAbstract:The quantitative relation between slow-wave periods and spiking activity was evaluated in vivo in canine small intestine during the fasted state. Experiments were performed in three conscious dogs with three bipolar electrodes, implanted respectively 10, 25 and 40cm beyond the ligament of Treitz. Digitized electrical recordings were automatically processed for the individual slow-wave periods and spike-burst intensities using a set of computer programs developed in our laboratory. A linear correlation existed between the degree of spiking activity and the average length of the preceding slow-wave period. The slopes of the regression lines were less steep for more distal electrodes. A second series of experiments showed that an increase in the slow-wave period precedes the onset of phase 3 of the Migrating Myoelectric Complex and that a fall in slow-wave period precedes the end of phase 3. These data show that a low slow-wave frequency is accompanied by a facilitation of spiking activity, whereas shortening of the slow-wave period is accompanied by a decrease in spike burst intensity. This relation between slow-wave period and spiking activity shows an aboral trend that may be related to intrinsic slow-wave frequency.
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Variation of slow-wave frequency and locking during the Migrating Myoelectric Complex in dogs.
American Journal of Physiology-Gastrointestinal and Liver Physiology, 1991Co-Authors: P Caenepeel, Gaston Vantrappen, Jozef Janssens, W Janssens, A Accarino, Hendrik EyssenAbstract:Slow waves determine rhythm and polarity of spike bursts. We measured the variation of slow-wave frequency (swf) and locking (swl) in the canine jejunum during the various phases of the Migrating Myoelectric Complex (MMC) and during induced phase III (erythromycin 125 micrograms/kg iv bolus or somatostatin 2.5 micrograms.kg-1.h-1 iv infusion), blocked phase III (atropine 20 micrograms/kg iv bolus), and so-called stationary phase III activity (cisapride 150 micrograms/kg iv bolus). The EMG of 4 dogs, implanted with 10 bipolar electrodes, was recorded on a polygraph. Our results indicate that swf and swl change during the MMC from a stepwise swf gradient with slow waves locked in plateaus during phase I to a continuous swf gradient without or with significantly reduced phase locking during phase III. The length of the first swf plateau decreases significantly from 42 +/- 12 cm post Treitz during phase I to 11 +/- 4 cm during spontaneous phase III. Atropine block of phase III activity prevents phase unlocking and development of a continuous swf gradient. Our hypothesis is that phase unlocking may be one of the induction mechanisms of spike-burst activity.