Effect of motilin on the opossum upper gastrointestinal tract and sphincter of Oddi

We studied the effect of motilin on myoelectric activity of the sphincter of Oddi (SO) and upper gastrointestinal tract in conscious opposums. In 17 animals, bipolar electrodes were implanted on the gastric antrum, SO, duodenum, and jejunum. Subsequent 8-h recordings reconfirmed our previous findings that SO spike burst rate changed with interdigestive cycles of the gastrointestinal migrating myoelectric complex (MMC), becoming maximal during passage of phase III activity through the duodenum. In eight animals, peak motilin levels were shown to occur concurrently with maximal SO spike burst rate and MMC phase III activity in the duodenum. Motilin infusion (0.3 and 0.9 micrograms X kg-1 X h-1), given for 30-60 min starting 10 min after duodenal phase III, elicited premature MMC activity that originated in the stomach. Maximal SO activity occurred coincident with passage of premature phase III activity through the duodenum. Pulse intravenous doses of motilin (25-1,600 ng/kg) generally caused an immediate increase in spike burst activity in the gastric antrum, duodenum, and SO that lasted 3-5 min and was often followed by a premature MMC, usually starting in the antrum and progressing through the duodenum and jejunum. Increases in SO spike burst rate also occurred concurrent with motilin-induced, premature duodenal phase III. Motilin given at 5-60% of the duodenal MMC cycle length elicited premature MMCs at 10-60% of the cycle, but no premature MMCs were elicited by any of the motilin doses at the 5% intervals.(ABSTRACT TRUNCATED AT 250 WORDS)     

Interdigestive gastroduodenal manometry in humans. Indication of duodenal phase III as a retroperistaltic pump

To elucidate the specific function of the three phases (I-III) of the migrating motor complex (MMC) by manometry, detailed analysis of individual pressure waves in the proximal duodenum was performed. Twenty healthy subjects (10 men and 10 women of whom 11 were tube-naive) underwent computerized manometry for 5 h during fasting followed by 45 min after a meal using an 8-channel water perfused catheter. Three recording points were in the antrum, three in the proximal duodenum (2 cm apart), one in the distal duodenum and one in the proximal jejunum. In all subjects at least one phase III (median 2) was observed during the 5-h fasting recording. In the proximal duodenum the mean proportion of retrograde pressure waves, out of all propagating waves, was significantly increased in the last part of phase III (85 ± 9%, mean, SE), compared with early phase III (6 ± 5%), late phase II (5 ± 4%) and the feeding phase (10 ± 5%), irrespective of gender or previous tube-experience. The median length of the MMCs was 108.5 min. There was no statistically significant difference between men and women or between tube-naive and tube-experienced subjects for the duodeno-jejunal motility indices of phase II and phase III, nor for duration or migration of phase III. The postprandial motility index of the small intestine was increased compared with the interdigestive late phase II, particularly in the jejunum (P < 0.02). The last part of the duodenal interdigestive phase III in healthy subjects shows the feature of a retroperistaltic pump. This cyclic sequence of retropropagation coincides with the reported rapid alkalinization of the duodenal bulb and the gastric antrum occurring in early antral phase I.     

Indirect evidence for increased mechanosensitivity of jejunal secretomotor neurones in patients with idiopathic bile acid malabsorption

Aim: The interdigestive motor rhythm, the migrating motor complex (MMC), is accompanied by active secretion of chloride during periods of distally propagating maximal motor activity (MMC phase III). We studied the behaviour of this system in bile acid malabsorption (BAM), a relative common cause of chronic diarrhoea. We measured motor activity and transmucosal potential difference (PD, reflecting active chloride secretion), in the proximal jejunum in healthy controls (n = 18) and in a group of patients with BAM (n = 11). The phase III‐generated voltage was related to the degree of BAM quantified by the ⁷⁵SeHCAT test. Methods: We used a multi‐channel intestinal infusion system to simultaneously measure jejunal pressure and PD. Saline passing calomel half‐cells was infused into the jejunum and subcutaneously. Pressure and PD were recorded in the fasting state and after a test meal. Results: In the absence of motor activity, jejunal PD was not significantly different from zero in either group. During MMC phase III, PD reached significantly higher mean and peak levels in BAM patients. The product of MMC phase III length multiplied by voltage, over 3 h, was also significantly higher in BAM patients (controls: median 307 mV × cm, range 70–398; BAM: median 511, range 274–2271, P < 0.01). This value was also significantly correlated with the degree of BAM as reflected by the ⁷⁵SeHCAT test (P < 0.05). Conclusion: Phase III induced jejunal secretion may be upregulated in BAM patients, resulting in overload of colonic reabsorption capacity.     

Effect of rabbit antimotilin serum on myoelectric activity and plasma motilin concentration in fasting dog

It is known that a cyclic increase in plasma motilin concentration occurs during the interdigestive state of dog and the increase coincides with migrating myoelectric complexes (MMCs) of the antrum as well as proximal duodenum. The purpose of the present study is to determine the role of endogenous motilin in the occurrence of MMCs in 10 dogs prepared with a gastric cannula and platinum monopolar electrodes in the gastric antrum, duodenum, jejunum, and ileum. After recording at least two consecutive cycles of MMCs from the proximal duodenum, each dog received an intravenous infusion of highly specific rabbit antimotilin sera in varying doses ranging from 3.5 to 15 ml for a period of 60 or 90 min. During the motility recording period ranging from 6 to 30 h following the administration of the antimotilin serum, several changes in the motility were observed. 1) The occurrence of MMCs in the antrum, duodenum, jejunum, and ileum was temporarily interrupted for varying periods depending on the individual dog studied and the amount of antiserum administered. When the higher dose of antimotilin was administered, a more profound and prolonged inhibition occurred. 2) Phase I activity rarely occurred. Instead, a phase II-like activity continued throughout the recording period. 3) MMCs in the jejunum or ileum occurred at irregular intervals without aboral propagation of MMCs from the duodenum or jejunum. 4) The plasma motilin concentration decreased to levels lower than that observed during phase I of the duodenum and exhibited no cyclic increase until the MMCs reappeared in the proximal duodenum.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intestinal motility responses to neuropeptide γ in vitro and in vivo in the rat: comparison with neurokinin 1 and neurokinin 2 receptor agonists

We have studied the effect of a novel tachykinin, neuropeptide γ(NPγ) on small intestinal motility in the rat. Experiments were done in vitro on longitudinal muscle strips of duodenum, and in vivo on the migrating myoelectric complex (MMC) of the small intestine. In vitro, contractile effects of NPγ were compared with those of a selective neurokinin 1 (NK1) receptor agonist, substance P methyl ester (SPME), and a selective neurokinin 2 (NK2) receptor agonist, Nle¹⁰-NKA(4–10)(NleNKA). NPγ, SPME and NleNKA caused concentration-dependent contractions (P < 0.001). NPγ was eight-fold more potent than NleNKA, and 118-fold more potent than SPME. Contractile responses to NPγ were reduced by hexamethonium (P < 0.01) and atropine (P < 0.05). The non-selective NK receptor antagonist spantide I only slightly reduced the contractile response to NPγ, as did the selective NK1 antagonist GR 82334, and the selective NK2 antagonist L-659877 and MEN 10376. In vivo, effects of NPγ on the MMC were compared with those of the natural tachykinins substance P (SP) and neurokinin A (NKA). NPy disrupted the MMC and induced irregular spiking in a dose-dependent manner from 25 to 100 pmol kg^-1 min^-1 i.v. (P < 0.05). The effect of NPγ was more prominent than that of NKA at equal doses, while SP had no effect. Our findings show that NPγ exerts potent stimulatory effects on small intestinal motility, most likely mediated directly via distinct NK receptors on smooth muscle cells, but also indirectly via a cholinergic link.     

Role of Serotonin in the Recovery of Electrical Activity in the Stomach and Small Intestine of Rats during the Early Postsurgery Period

The effects of serotonin and 5-HT₄ receptor agonist cisapride on electrical activity of the stomach and small intestine were studied in rats with postoperative ileus. Postoperative ileus was accompanied by the absence of the migrating myoelectric complex in the stomach and small intestine. All phases of the migrating myoelectric complex were successively recovered in the jejunum, duodenum, and stomach. Administration of serotonin and 5-HT₄ receptor agonist cisapride into the jejunum was followed by the appearance of spike activity, which spread from the stomach to the jejunum. Intraintestinal treatment with cisapride and serotonin shortened the period to recovery of the migrating myoelectric complex to 3 and 4 days, respectively. Our results suggest that serotonin plays a role in the regulation of the migrating myoelectric complex at the early postoperation period. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 140, No. 11, pp. 511–514, November, 2005     

Relation between slow-wave frequency and spiking activity during the migrating myoelectric complex in dogs

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.     

Relationship between dietary-induced changes in intestinal commensal microflora and duodenojejunal myoelectric activity monitored by radiotelemetry in the rat in vivo

Interdigestive intestinal motility, and especially phase III of the migrating myoelectric/motor complex (MMC), is responsible for intestinal clearance and plays an important role in prevention of bacterial overgrowth and translocation in the gut. Yet previous results from gnotobiotic rats have shown that intestinal microflora can themselves affect the characteristics of the myoelectric activity of the gut during the interdigestive state. Given that the composition of the intestinal microflora can be altered by dietary manipulations, we investigated the effect of supplementation of the diet with synbiotics on intestinal microflora structure and the duodenojejunal myoelectric activity in the rat. To reduce animal distress caused by restraint and handling, which can itself affect GI motility, we applied radiotelemetry for duodenojejunal EMG recordings in conscious, freely moving rats. Thirty 16-month-old Spraque-Dawley rats were used. The diet for 15 rats (E group) was supplemented with chicory inulin, Lactobacillus rhamnosus and Bifidobacterium lactis. The remaining 15 rats were fed control diet without supplements (C group). Three rats from each group were implanted with three bipolar electrodes positioned at 2, 14 and 28 cm distal to the pylorus. After recovery, two 6 h recordings of duodenojejunal EMG were carried out on each operated rat. Subsequently, group C rats received feed supplements and group E rats received only control diet for 1 week, and an additional two 6 h recordings were carried out on each of these rats. Non-operated C and E rats were killed and samples of GI tract were collected for microbiological analyses. Supplementation of the diet with the pro- and prebiotics mixture increased the number of bifidobacteria, whereas it decreased the number of enterobacteria in jejunum, ileum, caecum and colon. In both caecum and colon, the dietary supplementation increased the number of total anaerobes and lactobacilli. Treatment with synbiotics increased occurrence of phase III of the MMC at all three levels of the small intestine. The propagation velocity of phase III in the whole recording segment was also increased from 3.7 +/- 0.2 to 4.4 +/- 0.2 cm min(-1) by dietary treatment. Treatment with synbiotics increased the frequency of response potentials of the propagated phase III of the MMC at both levels of the jejunum, but not in the duodenum. In both parts of the jejunum, the supplementation of the diet significantly decreased the duration of phase II of the MMC, while it did not change the duration of phase I and phase III. Using the telemetry technique it was demonstrated that changes in the gastrointestinal microflora exhibited an intestinal motility response and, more importantly, that such changes can be initiated by the addition of synbiotics to the diet.     

Effects of intestinal muscular wrapping on remnant intestinal motility after massive small bowel resection in conscious canines.

We searched the effect of the muscular valve on the management of short bowel syndrome. The motility of the remnant intestine with a special muscular valve after 80% massive distal small bowel resection (MSBR) was evaluated in conscious dogs. The valve (muscular ring) was made by the autointestinal muscle layer holding vascular pedicle. Interdigestive and postprandial bowel motility using bipolar electrodes and/or contractile strain gauge force transducers 2-4 weeks after the surgery, and data of this group (Group I) were compared to the motility in dogs after MSBR without valve construction (Group II) and in controls (Control). Results; Fasting duodenal migrating myoelectric (or motor) complexes (MMCs) in Group I occurred at longer intervals than in Control and almost similarly to those in Group II. MMCs arising from the duodenum were often interrupted before the jejunum above the valve and the anastomosis. The velocity of duodenal MMC propagation was slowed in every intestinal segment including that from the duodenum to the proximal jejunum, and to the jejunum above the anastomosis. Transit time in MSBR group (I and II) from the duodenum to the terminal ileum was extremely shorter than in Control, but there were no differences between in Groups I and II. The duration of the postprandial period without duodenal MMCs in Group I was significantly prolonged than in Control, but was shorter than that in Group II. The muscular valve was frequently activated, and the jejunum covered with the valve was contracted frequently which synchronized with the valve activity. It seemed the valve worked as sphincter. However, intestinal obstruction was not occurred through the jejunum covered by the valve. In conclusion, changes in gut motility after MSBR with the valve construction compensate for the shortened intestine and maintain the bowel content earlier postoperatively in comparison with the MSBR alone, and also contribute to the adaptive increase in the remnant intestinal absorption.     

Stability of Myoelectric Slow Waves and Contractions Recorded from the Distal Colon

The stability of physiological activity in the distal colon was investigated by recording 5-6 hours in each of 6 healthy adults. Contractions and myoelectric slow waves were recorded from the sigmoid colon (25-30 cm from the skin surface) and rectum (10-15 cm), and pressure waves were recorded from the proximal small intestine. The activity index (sum of areas of all waves divided by recording time) varied by 200% to 800% across 4-min samples for all motility and myoelectric slow wave recordings. Spectral analysis indicated that contractile activity waxed and waned in a cycle with a period of 40-55 min in the colon and 64-80 min in the small intestine. Myoelectric slow wave activity in the colon cycled with a period of 30-40 min. Contractile activity in the sigmoid colon was correlated with similar activity in the rectum, but myoelectric slow wave activity in the colon was not correlated with myoelectric slow waves in the rectum. The frequency composition of contractions and slow waves was unstable over time.     

Suppression of small intestinal motility and morphine withdrawal diarrhoea by clonidine: peripheral site of action

The effects of systemic administration of morphine (4.0 mg kg-1) and clonidine (2.5-10.0 micrograms kg-1), as well as the peripherally active alpha 2-adrenoceptor agonist oxymetazoline (2.8-11.2 micrograms kg-1), were studied on the migrating myo-electric complexes (MMCs) of the small intestine in conscious, naive rats. Furthermore, the effects of naloxone (1.0 mg kg-1) and the peripherally acting opioid antagonist, methylbromide naloxone (1.0-2.0 mg kg-1) were studied on the MMCs in morphine-dependent animals. Similar doses of clonidine or oxymetazoline inhibited the MMCs of the small intestine, which suggests a peripheral site of action of clonidine. Since naloxone (1.0 mg kg-1) did not antagonize the effect of clonidine, and yohimbine (1.0 mg kg-1) failed to antagonize the effect of morphine on the MMC, the inhibitory effects on intestinal motility of clonidine and morphine are mediated through different receptors. Morphine-dependent rats showed a prolonged interval between activity fronts and decreased propagation velocity of the activity fronts. Both naloxone (1.0 mg kg-1) and methylbromide naloxone (1.0-2.0 mg kg-1) induced intense spiking activity and profuse diarrhoea. Clonidine (5.0-10.0 micrograms kg-1) as well as oxymetazoline (5.6-11.2 micrograms kg-1) given prior to naloxone prevented the intense spiking as well as the concomitant diarrhoea. We conclude that the potent inhibition of small intestinal myoelectric activity by alpha 2-adrenoceptor agonists is mainly executed via peripheral mechanisms. This effect may contribute to their beneficial action in morphine withdrawal diarrhoea, and partly underlie a general antidiarrhoeal action.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of neurotensin and neurotensin analogues on the migrating myoelectrical complexes in the small intestine of rats

The purpose of the present experiments was to study the effect of neurotensin and neurotensin analogues on the migrating myoelectrical complexes in the small intestine of rats. Four bipolar electrodes were implanted into the muscular wall of the small intestine. The electrodes were placed 5, 15, 25 and 35 cm distal to the pylorus. 7–10 days after the operation the animals were fasted for 48 h with free access to water. Some experiments were performed on conscious rats and in others the rats were anesthetized with pentobarbital, 30 mg/kg. I.v. infusion of either neurotensin (NT) or (Gln⁴)-neurotensin at doses of 1.8, 3.6 and 7.1 pmol kg^-1· min^-1abolished the migrating myoelectric complexes, which were replaced by increased spiking activity along the whole length of the small intestine from which activity was recorded. The changes in myoelectrical activity were observed within 2–4 min after commencement of the infusion. The activity returned to control levels within 5–15 min after the end of the infusion period. The neurotensin sequences NT 9–13, NT 8–13, NT 4–13, NT 1–9 and (Gln⁴)-NT 1–11 did not induce any changes in the electrical activity in the small intestine. The effects of NT and (Gln⁴)-neurotensin on the myoelectrical activity in the small intestine were indistinguishable. The changes induced by NT or (Gln⁴)-NT resemble those found after the ingestion of food. The present data indicate that the intact NT sequence, rather than smaller NT fragments, is necessary to induce changes in myoelectrical activity in the small intestine.     

Wiener filtering of surface EMG with a priori SNR estimation toward myoelectric control for neurological injury patients

Voluntary surface electromyogram (EMG) signals from neurological injury patients are often corrupted by involuntary background interference or spikes, imposing difficulties for myoelectric control. We present a novel framework to suppress involuntary background spikes during voluntary surface EMG recordings. The framework applies a Wiener filter to restore voluntary surface EMG signals based on tracking a priori signal to noise ratio (SNR) by using the decision-directed method. Semi-synthetic surface EMG signals contaminated by different levels of involuntary background spikes were constructed from a database of surface EMG recordings in a group of spinal cord injury subjects. After the processing, the onset detection of voluntary muscle activity was significantly improved against involuntary background spikes. The magnitude of voluntary surface EMG signals can also be reliably estimated for myoelectric control purpose. Compared with the previous sample entropy analysis for suppressing involuntary background spikes, the proposed framework is characterized by quick and simple implementation, making it more suitable for application in a myoelectric control system toward neurological injury rehabilitation.     

不同状态下家兔Oddi括约肌肌电活动实验模型的建立

目的建立不同状态下家兔Odd i括约肌(sph incter ofOdd i,SO)肌电活动实验模型。方法利用电生理方法记录家兔Odd i括约肌的肌电活动,并建立空腹、进食、药物兴奋和药物抑制等四种状态下Odd i括约肌肌电活动的实验模型。结果空腹状态下家兔SO肌电表现为规律的、单发性的锋电位(sp ike potentials of SO,SPSO);禁食18 h后,给予50 m l牛奶,SO肌电表现为规律的、间断的肌电簇(myoelectron ic activity of SO,MASO);静脉注射1 mg吗啡和2 mg新斯的明后,SO肌电活动首先表现为数个长时间、不间断的SPSO组成的肌电串,120~150 m in内完全抑制,抑制期过后又恢复单个SPSO;静脉给予山莨菪硷1 mg,SPSO随即消失。结论成功建立了四种状态下家兔Odd i括约肌肌电活动实验模型。     

Association between gastric myoelectric activity disturbances and dyspeptic symptoms in gastrointestinal cancer patients

PurposeDyspeptic symptoms present a severe problem in gastrointestinal (GI) cancer patients. The aim of the study was to analyze an association between gastric myoelectric activity changes and dyspeptic symptoms in gastrointestinal cancer patients.Material and MethodsThe study included 80 patients (37 men and 43 women, mean age 61.2 ± 7.8 years) diagnosed with GI tract malignancies: colon (group A), rectal (group B) and gastric cancers (group C). Gastric myoelectric activity in a preprandial and postprandial state was determined by means of a 4-channel electrogastrography. Autonomic nervous system was studied based on heart rate variability analysis. The results were compared with the data from healthy asymptomatic controls.ResultsIn a fasted state, GI cancer patients presented with lesser percentages of normogastria time (A:44.23 vs. B:46.5 vs. C:47.10 vs. Control:78.2%) and average percentage slow wave coupling (ACSWC) (A:47.1 vs. B:50.8 vs. C:47.2 vs. Control:74.9%), and with higher values of dominant power (A:12.8 vs. B:11.7 vs. C:12.3 vs. Control:10.9) than the controls. Patients did not show an improvement in the percentage of normogastria time, dominant power, dominant frequency and ACSWC in response to food. The severity of dyspeptic symptoms correlated with the values of electrogastrography parameters. Patients showed lower values of heart rate variability parameters than the healthy controls, that indicate abnormal autonomic nervous system activity.ConclusionGI cancers affect the gastric myoelectric activity, decreasing normogastria and slow wave coupling. These patients do not show adequate gastric motility response to food. Impaired gastric electric motility may result from cancer-induced autonomic disturbances.     

Small-intestinal myoelectric activity in sheep: rebound excitation versus phase-3-like activity revealed by hexamethonium and atropine administration

Postinhibitory or rebound excitation (RE) is a known phenomenon in gastrointestinal motility, but its precise character and triggering mechanisms have not been defined so far. This study was thus devoted to analyzing its occurrence following hexamethonium (Hx) and atropine (At) administration during various phases of the migrating myoelectric or motor complex (MMC) in fasted, non-fasted, and fed sheep and to determine the nature of RE in comparison with phase 3 of the small-intestinal MMC. In the course of chronic experiments, various doses of Hx and At evoked RE alternating with phase-3-like activity (not the organized phase 3 of the MMC or its fragments) with periods and intensities related to the drug dose. In non-fasted sheep these changes were less pronounced and more delayed, while after feeding no excitatory response was observed. When the drug was given during phase 1 of the MMC, RE did not occur or was greatly reduced and delayed. Hx triggered RE mostly in the duodenum and At mostly in the jejunum. Rather, no RE was observed in the ileum. It is concluded that Hx and At inhibit small-intestinal motility and evoke RE and phase-3-like activity as a secondary stimulatory response in conscious sheep.     

Use of peripheral electrography to evaluate synchronism of electrical activity in different parts of the gastrointestinal tract

Use of the technique of peripheral electrography to study electrical activity in various parts of the gastrointestinal tract in dogs after fasting and during digestion is described, and it is shown that a computerized spectral analysis of peripheral electrograms makes it possible to monitor the cycle of fasting periodic gastrointestinal activity. In the process of digestion, the cycle of fasting periodic activity is disrupted and nonadjacent areas of the gastrointestinal tract exhibit synchronous electrical activity. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 1, pp. 9–12, January, 1995 Presented by V. D. Fedorov, Member of the Russian Academy of Medical Sciences     

Enhanced intestinal motility influences absorption in anaesthetized rat

The subject of this investigation was to study influence of the intestinal motility on absorption of 3‐o‐methyl‐D ‐glucose (3‐OMG), mannitol and polyethylene glycol (PEG 4000), used as absorption route markers, while monitoring cardiovascular parameters in an intestinal in situ model in rats. Rats were anaesthetized with Inactin^® and Rapinovet^®. A segment of duodenum, approximately 10 cm, was perfused single‐pass with saline containing unlabelled and radioactive 3‐OMG, PEG 4000 or mannitol. The PEG 4000 was recovered almost completely in the intestinal perfusate suggesting an intact mucosal integrity. Most animals exhibited an intestinal contractile activity resembling fed motility except seven out of 19 given Rapinovet^®, which showed a ‘burst‐type’ pattern resembling migrating motor complex (MMC). Absorption of 3‐OMG in rats with MMC‐like motility appears to be lower than in rats with fed‐like motility, while no such difference was seen for mannitol. Moreover, there was a positive correlation (r ²=0.75) between intestinal activity (fed) and absorption of 3‐OMG, but not with absorption of mannitol. The carrier‐mediated absorption of 3‐OMG was not only influenced by intestinal motility, but also by its pattern. This was not observed with mannitol, which is passively absorbed.     

Effects of ranitidine and oxmetidine on gastrointestinal motility in conscious dog

Two histamine H₂-receptor antagonists ranitidine and oxmetidine were tested for their effects on gastrointestinal motility in conscious fasted dogs chronically fitted with intraparietal electrodes on the antrum, duodenum and jejunum. Intravenous administration of ranitidine (3 mg/kg) stimulated gastrointestinal spiking activity through a cholinergic mechanism and increased the duration of the cycles of migrating myoelectric complexes. Oxmetidine at the same dose did not modify the gastrointestinal motor profile. These results showed clearcut differences in nonspecific effects of two H₂-antagonists equipotent on gastric acid secretion.To whom correspondence should be addressed.     

Roux-en-Y or 'uncut' Roux procedure? Relation of intestinal migrating motor complex recovery to the preservation of the network of interstitial cells of Cajal in pigs

We designed a conscious pig model to investigate myoelectric activity and the number of interstitial cells of Cajal (ICC) in the proximal jejunum following the Roux-en-Y and 'uncut' Roux procedures in relation to clinical outcomes. Twelve male Polish White pigs (8 weeks old, 10-13 kg) underwent surgery under general anaesthesia first to implant bipolar electrodes and telemetry transmitters for continuous electromyography recordings and then, after 1 week recovery, to create Roux-en-Y (n = 6) and 'uncut' Roux loops (n = 6). Upper gut tissue specimens were studied for the expression of c-kit staining procedure to quantitatively identify the presence of interstitial cells of Cajal. The intestinal migrating motor complex was restored within 10.5 and 37 h in 'uncut' Roux and Roux-en-Y pigs, respectively (P < 0.05). During 2 weeks, the 'uncut' Roux piglets increased their body weight by 18.0%, whereas the Roux-en-Y piglets increased their body weight by only 7.3% (P < or = 0.05). Two weeks after surgery, the number of ICC located in the region of Auerbach's plexus was higher and adhesions in the abdominal cavity lower in the 'uncut' Roux group. In conclusion, in the pig model, preservation of smooth muscle and ICC network continuity in the proximal jejunum may play an important role in early postsurgical recovery.