Intestinal Motility In Dogs Research Articles

Time-related effects of benzodiazepines on intestinal motility in conscious dogs.

The effects of diazepam and GABA on intestinal motility were investigated in fasted dogs fitted with strain-gauge transducers. Injected intravenously at 9.00 and 16.00 h, diazepam (0.5 mg kg-1) affected intestinal motility only during darkness i.e. from 19.00 to 7.00 h. These jejunal motor effects which were mimicked by GABA, (0.3 mg kg-1 i.v.) corresponded to a disruption of the migrating myoelectric complex (MMC) with an increased contractile activity. These results demonstrate that benzodiazepines affect the intestinal motility in dog and suggest that the effects are related to sleep-stages.

W1230 Excitatory Effects of Electroacupunture On Small Intestinal Motility in Dogs

Background and Aims: While intestinal motility disorders are common, the treatment options are rather limited. Electroacpuncture (EA) is known to improve gastric motility and emptying. The aim of this study was to investigate effects of EA on small intestinal motility in dogs. Methods: Six dogs were chronically implanted with 2 cannulas (one in the proximal and the other in the distal small intestine). Intestinal manometry and transit were assessed four times on 4 separate days in a randomized order: Control (saline injection), glucagon injection, glucagon plus EA, and glucagon plus EA plus naloxone. In control or glucagon session, after an overnight fast, a baseline recording of small intestinal contractions was made for a period of 30 min and then each dog was fed with a 237 ml liquid meal mixed with 100mg phenol red, and small intestinal contractions and transit were recorded simultaneously until the completion of intestinal transit (disappearance of phenol red in the chyme collected from the distal cannula). Saline or glucagon (2.87 x 10 -2 μmol/kg) was bolus injected immediately after the feeding in control or glucagon session respectively. In the EA and EA+naloxone sessions, EA was performed for a period of 15 min during Phase I of the migrating motor complex (MMC) and 30min after the meal and naloxone (1mg/kg, IV) was given 50 min before the meal. EA was delivered bilaterally at ST36 which is one of the most frequently used acupuncture points for the treatment of gastrointestinal diseases. Intestinal transit was assessed by the disappearance of phenol red and intestinal contraction was determined by the contractile index (CI: sum of the area under the curve of each contraction). Results: 1) EA induced small intestinal contractions during phase I of the (MMC) (CI: 4.4 ±0.8 at baseline vs. 8.3 ± 0.7 during EA, P =0.005); 2) in the fed state, EA significantly improved glucagon-induced small intestinal postprandial hypomotility (CI: 3.8 ± 0.4 vs. 6.1 ± 0.6, P =0.001); 3) EA significantly accelerated small intestinal transit delayed by glucagons (67.9 ± 4.3 vs. 40.2 ± 5.0 min, P =0.003); 4) there was a negative correlation between the CI and transit time (r = 0.427, = 0.039); and 5) the excitatory effect of EA was blocked by naloxone. Conclusions: EA enhances small intestinal contractions in both fasting and fed states and accelerates intestinal transit slowed by glucagon. EAmay have a therapeutic potential for treating patients with small intestinal motility disorders.

238 Effects of Rimonabant On Gastric and Small Intestinal Motility in Dogs

1 Decrease in abdominal pain or discomfort ≥1.0 (5-pt scale) for ≥9 wks 2 CSBMs ≥3 and increased ≥1 and straining/BSFS ≥1.0 (5-pt/7-pt scale) for ≥9 wks 3 'Yes' on binary scale for ≥9 wks 4 Completely/considerably relieved ≥6 wks or at least somewhat relieved all 12 wks 5 Completely relieved for ≥2 wks or at least considerably relieved for all 4 wks for ≥2 mos 6 Improvement ≥1.0 (5-pt scale) for ≥9 wks 7 Decrease ≥50% in 500-pt IBSSSS scale at Week 12

W1234 A Comparison of Small Bowel pH Profiles in Healthy Subjects and Patients with Gastroparesis As Measured By a Non-Invasive Wireless Capsule

Background and Aims: While intestinal motility disorders are common, the treatment options are rather limited. Electroacpuncture (EA) is known to improve gastric motility and emptying. The aim of this study was to investigate effects of EA on small intestinal motility in dogs. Methods: Six dogs were chronically implanted with 2 cannulas (one in the proximal and the other in the distal small intestine). Intestinal manometry and transit were assessed four times on 4 separate days in a randomized order: Control (saline injection), glucagon injection, glucagon plus EA, and glucagon plus EA plus naloxone. In control or glucagon session, after an overnight fast, a baseline recording of small intestinal contractions was made for a period of 30 min and then each dog was fed with a 237 ml liquid meal mixed with 100mg phenol red, and small intestinal contractions and transit were recorded simultaneously until the completion of intestinal transit (disappearance of phenol red in the chyme collected from the distal cannula). Saline or glucagon (2.87 x 10 -2 μmol/kg) was bolus injected immediately after the feeding in control or glucagon session respectively. In the EA and EA+naloxone sessions, EA was performed for a period of 15 min during Phase I of the migrating motor complex (MMC) and 30min after the meal and naloxone (1mg/kg, IV) was given 50 min before the meal. EA was delivered bilaterally at ST36 which is one of the most frequently used acupuncture points for the treatment of gastrointestinal diseases. Intestinal transit was assessed by the disappearance of phenol red and intestinal contraction was determined by the contractile index (CI: sum of the area under the curve of each contraction). Results: 1) EA induced small intestinal contractions during phase I of the (MMC) (CI: 4.4 ±0.8 at baseline vs. 8.3 ± 0.7 during EA, P =0.005); 2) in the fed state, EA significantly improved glucagon-induced small intestinal postprandial hypomotility (CI: 3.8 ± 0.4 vs. 6.1 ± 0.6, P =0.001); 3) EA significantly accelerated small intestinal transit delayed by glucagons (67.9 ± 4.3 vs. 40.2 ± 5.0 min, P =0.003); 4) there was a negative correlation between the CI and transit time (r = 0.427, = 0.039); and 5) the excitatory effect of EA was blocked by naloxone. Conclusions: EA enhances small intestinal contractions in both fasting and fed states and accelerates intestinal transit slowed by glucagon. EAmay have a therapeutic potential for treating patients with small intestinal motility disorders.

Excitatory effects of synchronized intestinal electrical stimulation on small intestinal motility in dogs

The aim of this study was to investigate effects of synchronized intestinal electrical stimulation (SIES) on small intestinal motility in dogs. Seventeen dogs were equipped with a duodenal cannula for the measurement of small bowel motility using manometry; an additional cannula was equipped in six of the dogs with 1.5 m distal to the first one for the measurement of small intestinal transit. Two pairs of bipolar electrodes were implanted on the small intestinal serosa with an interval of 5 cm; glucagon was used to induce postprandial intestinal hypomotility. Eleven dogs were used for the assessment of the small intestinal contractions in both fasting and fed states. The other six dogs were used for the measurement of small intestinal transit. We found that 1) SIES induced small intestinal contractions during phase I of the migrating motor complex (MMC) (contractile index or CI: 5.2 +/- 0.6 vs. 10.3 +/- 0.7, P = 0.003); 2) in the fed state, SIES significantly improved glucagon-induced small intestinal postprandial hypomotility (CI: 3.4 +/- 0.5 vs. 6.0 +/- 0.3, P = 0.03); 3) SIES significantly accelerated small intestinal transit delayed by glucagon (70.4 +/- 3.1 vs. 44.5 +/- 3.1 min, P < 0.01); 4) there was a negative correlation between the CI and transit time (r = -0.427, P = 0.048); and 5) the excitatory effect of SIES was blocked by atropine. SIES may have a therapeutic potential for treating patients with small intestinal disorders.

12 Effects of synchronized intestinal electrical stimulation on small intestinal motility in dogs

Our previous studies showed that synchronized gastric electrical stimulation enhanced antral contractions, accelerated gastric emptying in dogs. It has never been reported whether synchronized electrical stimulation could improve small intestinal motility. The aim of this study was to investigate the effects of synchronized intestinal electrical stimulation (SIES) on small bowel motility in both fasting and fed states in dogs.Methods: Five healthy female dogs (18–24 kg) were equipped with a duodenal cannula for the measurement of small bowel motility using manometry. Two pairs of bipolar electrodes were implanted on the small intestinal serosa with an interval of 25 cm; the first one was 10 cm beyond the pylorus and used for stimulation. The experiment was consisted of four sessions in each dog with a randomized order. In the fasting state, 20 min after occurrence of phase III, SIES was initiated and maintained for 45 min, small bowel motility was recorded during the entire experiment, and no stimulation was performed in the control session. In other two sessions, dogs were fed with solid meal at the beginning of the experiment; glucagon (0.1 mg kg­1) was injected 20 min after feeding, SIES was initiated at the same time for 20 min followed by 20 min recovery period. The stimulus was composed of train of pulses with on‐time of 0.5 s, frequency of 20 Hz, pulse width of 2 ms and amplitude of 4 mA.Results: 1). In the fasting state, SIES induced small intestinal contractions during phase I. The motility index was 5.2 ± 0.6 in the control session and significantly increased to 10.3 ± 0.7 with SIES (P = 0.003). 2). In the fed state, glucagon substantially and significantly inhibited small intestinal motility. The motility index was 11.3 ± 0.7 after feeding and reduced to 3.4 ± 0.5 with glucagon injection (P &lt; 0.001). SIES significantly enhanced glucagon‐induced small intestinal postprandial hypomotility. The motility index was 3.4 ± 0.5 in the control session and increased to 6.0 ± 0.3 with the presence of SIES (P = 0.03).Conclusions: Intestinal electrical stimulation synchronized with intestinal slow waves induces intestinal contractions during phase I and enhanced small intestinal postprandial hypomotility induced by glucagon. SIES may have the therapeutic potential for treating small intestinal motility disorders. (Supported by a grant from American Diabetes Association).

Application of pulsed Doppler ultrasound for the evaluation of small intestinal motility in dogs

The purpose of this study was to verify whether small intestinal peristalsis could be observed and quantitatively assessed using pulsed-Doppler ultrasound. Pulsed-Doppler ultrasound was used to evaluate small intestinal peristalsis after a meal in ten normal dogs and ten sedated dogs. The small intestinal peristalses were measured 0, 1, 3, 6, 9, 12, and 24 hours after a 24-hour fast and after feeding. The number of small intestinal peristalsis were 0.133/min, 0.100/min, 0.033/min, 0.167/min, 0.070/min, 0.067/min, and 0.100/min in the fasted dogs, and 1.667/ min, 0.933/min, 1.133/min, 1.234/min, 1.933/min, 1.533/ min, and 0.533/min in fed dogs, respectively. In the dogs sedated with xylazine HCl, the number of small intestinal peristalsis was significantly reduced (p<0.01). However, in the dogs treated with ketamine HCl and acepromazine, the number of small intestinal peristalsis remained unchanged. Therefore, it can be concluded that pulsed-Doppler ultrasound allows graphic visualization of the intestinal movements, which can be subjected to qualitative and quantitative analysis, and may be suitable for a non-invasive study of small intestinal motility.

Effects of a selective and a nonselective muscarinic cholinergic antagonist on heart rate and intestinal motility in dogs.

The effects of methoctramine, a cardioselective muscarinic cholinergic antagonist, on heart rate and small intestinal motor activity were compared to those of the nonselective competitive muscarinic antagonist, atropine. Methoctramine or atropine, 6, 10, 30, 60 micrograms/kg, or sterile isotonic saline, was administered intravenously to six conscious dogs in cross-over studies. Methoctramine administration caused dose-dependent tachycardia without affecting intestinal motility, while atropine administration caused dose-dependent tachycardia accompanied by significant reductions in small intestinal motility. Additionally, methoctramine did not inhibit intestinal smooth muscle contractile activity initiated by the muscarinic agonist bethanechol, while atropine inhibited bethanechol-induced contractile activity in a dose-dependent manner. Calculated, dosages of methoctramine and atropine required to produce a 50% increase in heart rate over baseline were 35.1 +/- 5.3 and 39.5 +/- 6.2 micrograms/kg, respectively. This dosage of atropine caused a 93 +/- 13.9% reduction in intestinal motility. These findings suggest that selective muscarinic antagonists may be useful drugs for those veterinary patients in which nonselective muscarinic antagonists have the potential to produce untoward effects on intestinal motility.

Resulting long-term intestinal motility in dogs following construction of a reversed jejunal segment after extensive small bowel resection

To evaluate the long-term function and effective motility of a reversed jejunal segment after extensive small bowel resection, the authors continuously measured postoperative bowel motility during interdigestive and postprandial periods in conscious dogs 6 to 10 months after surgery. The long-term findings were compared with previously reported short-term results measured 2 to 4 weeks after the operation. In the long-term follow-up dogs with a 20-cm reversed jejunal segment constructed after extensive (75% to 80%) small bowel resection, the fasting duodenal migrating myoelectric (or motor) complex (MMC) was often interrupted in the jejunum above the reversed segment, and did not migrate smoothly to the reversed segment or terminal ileum. The MMCs arising from the duodenum predominantly propagated to the ileum through the inherent anatomic continuity of the bowel. In addition, brief small discordant contractions were frequent in the reversed segment and the jejunum, above the proximal anastomosis. These findings are similar to those of the MMC propagation pattern noted 2 to 4 weeks after surgery. However, the postprandial duration without duodenal MMC activity was significantly shorter in the dogs with long-term follow-up than in those with short-term follow-up (both were longer than in control dogs). Marked dilatation of the jejunum and reversed jejunal segment was noted across the proximal anastomosis. These results suggest that the transit time and passage of intestinal contents can be delayed and stagnated for at least 10 months after extensive small bowel resection with a 20-cm reversed jejunal segment. Although reports on the polarity of peristalsis in the reversed segment in long-term follow-up have been contradictory in both experimental and clinical studies, this research supports the conclusion that the reversed jejunal segment maintains its inherent propagative polarity and pattern over a long postoperative period.

Studies on intestinal motility and mechanism of cholangitis after biliary reconstruction

Cholangitis is a serious complication of biliary reconstruction for congenital biliary atresia. To observe the effect of intestinal motility on the mechanism of cholangitis, we studied intestinal motility in dogs after experimental common duct ligation and reconstruction by Roux-en-Y or interposition cholecystojejunostomy. One year after operation, bipolar electrodes were implanted in the canine intestine and electromyograms were performed. Distinct patterns of propagation and the direction of intestinal motility characteristic of each procedure were observed. The animals with Roux-en-Y loops showed a decrease in motility of the duodenum and upper jejunum. Those with an interposed segment demonstrated stagnation in both the duodenum and jejunum, and poor coordination of intestinal movement. The myoelectric activity of the Roux-en-Y loop suggests that it is the reconstruction technique most likely to prevent reflux cholangitis.

Interdigestive intestinal motility in dogs with chronic exclusion of bile from the digestive tract.

To elucidate the role of bile delivery into the duodenum on the regulation of plasma motilin and on the interdigestive migrating complex, three dogs were operated upon to ligate the main bile duct and divert the biliary flow into the urinary bladder via a Foley catheter. After the operation, despite the chronic diversion of bile from the digestive tract, all animals maintained an excellent health status and exhibited recurrent periods of phase III motor activity migrating from the duodenum to the ileum, which were associated with cyclic increases in plasma motilin. Following the infusion of pooled dog bile (1 mL/min for 10 min) into the duodenum, a premature phase III and a concomitant rise in plasma motilin were observed. These results suggest, that although bile delivery into the duodenum can induce motilin increase in plasma and period of phase III activity in the gut, this phenomenon does not constitute an essential stimulus for the release of motilin and for the induction of the phase III of the interdigestive migrating complex.

Pancreatic polypeptide and intestinal motility in dogs.

This study was designed to determine the potential role of endogenous PP in the control of intestinal motility by correlating plasma PP levels with motility patterns in fasted and fed dogs without and with administration of exogenous PP and rabbit PP antiserum. After an overnight fast, when the interdigestive myoelectric activity was recorded in each dog, mean basal PP at phase I averaged 35 +/- 7 pM with peaks of 52 +/- 5 pM coinciding with phase III (MMC) in duodenum. Postprandial rise in PP reached the peak level of 280 +/- 70 pM at the end of 1 hr after a meal when MMC was interrupted and replaced by fed-type motility pattern. Exogenous PP in a dose of 100 pmol/kg/hr infused when the phase III of the MMC passed mid-jejunum raised plasma PP to the level of 130 +/- 27 pM but failed to affect the spike activity or MMC periodicity. PP given in doses of 200 and 400 pmol/kg/hr, which raised plasma PP to 298 +/- 25 and 453 +/- 24 pM, respectively, increased dose dependently (but did not abolish) the MMC intervals and an overall spike activity due to the prolongation of phase II of the MMC. After termination of PP infusion, phase III-like activity appeared within 7-10 min. Injection of highly specific PP antiserum, which caused almost complete disappearance of plasma PP both in fasted and fed dogs, did not affect the MMC interval but increased spike activity in fasted animals and failed to affect significantly spike activity in fed animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Central effects of growth hormone-releasing factor (GRF) on intestinal motility in dogs: Involvement of dopaminergic receptors

The effects of intracerebroventricular (ICV) and intravenous (IV) administration of human pancreatic growth hormone-releasing factor (hpGRF) on gastro-intestinal motility were examined in fasted and fed conscious dogs equipped with chronically implanted strain-gages on the antrum and the jejunum. During the fasted state, hpGRF injected ICV at 0.1 μg·kg −1 or IV at 0.5 μg·kg −1 did not affect the cyclic occurrence of the migrating motor complex (MMC). This pattern was normally disrupted for 8–10 hours by a daily standard meal. Injected ventricularly (0.1 μg·kg −1) but not intravenously (0.5 μg·kg −1) 10–15 min after the daily meal, hpGRF significantly reduced ( p<0.01) the duration of the jejunal fed pattern ( 2.0±1.4 vs. 8.4±1.1 hours for control) but not that of the stomach. This effect persisted when hpGRF (0.1 μg·kg −1 ICV) was administered after indomethacin (2 mg·kg −1 IM), naltrexone (0.1 mg·kg −1 IV) or domperidone (1 mg·kg −1 IV) but was abolished by a previous IV injection of metoclopramide (1 mg·kg −1). It was concluded that hpGRF is able to act centrally to control the pattern of jejunal motility in fed but not in fasted dog, its effect being probably mediated through dopaminergic pathways.

Postoperative intestinal motility in dogs and sheep.

Electrical activity of the small intestine was recorded from chronically implanted electrodes in dogs and sheep. The effects of laparotomy and surgical procedures were identified under general anesthesia. Laparotomy induced in both species a complete inhibition of electrical spiking activity during the stage of muscular and peritoneal incision. The inhibitory period due to laparotomy was shorter in dogs than in sheep and in both species less marked at the duodenal level. A secondary period of inhibition (ileus) lasting from 6 hr for a resection of the colon to 24 hr for a transection of the small bowel was observed in dogs after a transient phase of normal activity during 3-6 hr. The period of inhibition due to abdominal surgery lasted from 48 to 72 hr and occurred at the time of surgery in sheep. In both species, inhibition due to laparotomy and surgical procedures was prevented by splanchnicectomy. The results showed that myoelectric activity of the different parts of the small intestine is specifically inhibited and/or disorganized through peripheral reflex pathways. They are activated at different degrees by laparotomy and abdominal surgery.

Autonomic inhibition of intestinal motility in dogs associated with intra-abdominal injury.

Autonomic inhibition of intestinal motility in dogs associated with intra-abdominal injury.