Effect of butorphanol, pentazocine, meperidine, or metoclopramide on intestinal motility in female ponies

Effect of butorphanol, pentazocine, meperidine, and metoclopramide on jejunal and pelvic flexure myoelectric and mechanical activity in 4 female ponies was investigated. The agent to be tested or saline solution was administered IV at the start of a 6-hour recording trial. In the jejunum, duration between activity fronts of regular spiking activity, defined as the length of the migrating myoelectric complex (MMC), was measured. The average duration of the MMC during control trials was 150 +/- 46 minutes. The average duration of the MMC after meperidine, butorphanol, pentazocine, and metoclopramide administration was 295 +/- 70 minutes, 260 +/- 60 minutes, 275 +/- 60 minutes, and 163 +/- 64 minutes, respectively. Meperidine, butorphanol, or pentazocine significantly increased the MMC duration (P less than 0.05), and did not significantly alter the pelvic flexure activity. Seemingly, meperidine, butorphanol, and pentazocine inhibited cyclic myoelectric activity in the jejunum. Metoclopramide had no effect on jejunal or pelvic flexure motility.     

Effect of Escherichia coli heat-labile enterotoxin on the myoelectric activity of the duodenum in weaned pigs

The objective of the present study was to elucidate the effect of subclinical doses of Escherichia coli heat-labile enterotoxin (LT) on the antro-duodenal myoelectric activities of weaned pigs. Twelve weaned pigs were surgically implanted with three pairs of electrodes on the antrum 3 cm before the pylorus, 5 and 20 cm after the pylorus on the duodenum, respectively. An infusion cannula was inserted into the duodenum between duodenal electrodes. Using a wireless telemetry recording system, an electromyography (EMG) tracing lasting at least 24 h was recorded as the control, then another 24-h EMG recording was performed with a bolus intraduodenal infusion of LT (0.1 and 0.5 microg/kg b.w.). After a 1- to 2-day break, a 5-fold higher dose of LT was administered using the same protocol. In the antrum, LT administration barely modified the EMG signal. However, in the duodenum it prolonged the duration of phase II and the migrating myoelectric complex (MMC) cycle when compared with the control. The number of duodenal MMC cycles was also significantly diminished. Moreover, the migrating velocity of phase III was increased. The migrating action potential complex (MAPC) was present both without and with LT, but occurred more frequently following LT administration. In conclusion, LT caused a dose-dependent, lagged alteration in the duodenal MMC in weaned pigs, involving a reduction of the MMC number by lengthening phase II, increased phase III migration velocity, and increased MAPC frequency. The disturbances did not, however, result in diarrhoea and may reflect the induction of a local protection mechanism of the gut to expel unwanted foreign content from the lumen of the upper gut.     

EVALUATION OF THE GASTROINTESTINAL TRACT IN DOGS USING COMPUTED TOMOGRAPHY

Abdominal computed tomography (CT) studies of 19 dogs with no history or clinical signs of gastrointestinal disease, and two dogs with a histological diagnosis of gastrointestinal neoplasia were examined retrospectively. Gastrointestinal segments were evaluated subjectively for conspicuity, contrast enhancement, and wall layering after contrast medium administration. In dogs without gastrointestinal disease, there were 62.8% of gastrointestinal segments (serosa to serosa) and 77.7% of gastrointestinal walls (serosa to mucosa) visualized. Wall layering on postcontrast images was seen in 21.8% of gastrointestinal segments. There was significant association between gastrointestinal diameter and wall thickness. There was significant association between weight and gastrointestinal wall thickness in the following regions: gastric fundus, gastric body, gastric pylorus, gastric pyloric antrum, duodenal cranial flexure, jejunum and ascending colon, and between patient weight and gastrointestinal diameter in cranial duodenal flexure, descending duodenum, transverse duodenum, ascending duodenum, and jejunum. Measurements acquired from CT studies correlated well with previously published normal reference ranges for radiographic and ultrasonographic studies. Gastrointestinal neoplasia, diagnosed in two dogs, had a gastrointestinal wall thickness greater than the range of the dogs without gastrointestinal disease. Computed tomography offers identification of the gastrointestinal tract segments in dogs, allows for evaluation of gastrointestinal diameter and aids in investigation of gastrointestinal wall thickness.     

Evaluation of metoclopramide hydrochloride as an aid for passage of a flexible endoscope into the duodenum of dogs.

The purposes of this study were to evaluate the efficacy of metoclopramide to aid passage of a flexible endoscope into the duodenum of dogs, and to determine whether the effect of metoclopramide is dependent on dose. In a randomized, blinded, complete-block design, 6 healthy dogs were anesthetized, then each was given saline solution or 1 of 4 doses of metoclopramide on different days. The ease of passage of a flexible, fiberoptic gastroscope through the pylorus was assessed independently by 3 endoscopists. Administration of metoclopramide hydrochloride at a dosage of 0.4 mg/kg of body weight, iv, made passage of a flexible endoscope into the duodenum significantly (P = 0.009) more difficult than when saline solution was administered; however, dosages of 0.1, 0.2 and 0.8 mg of metoclopramide/kg did not (P = 0.489, 0.842, and 0.092 respectively). It was concluded that metoclopramide did not facilitate, and at one dosage hindered, successful passage of a flexible endoscope into the duodenum of healthy dogs under the conditions of the study. Metoclopramide, therefore, cannot be recommended as an aid for passage of a flexible endoscope into the duodenum of dogs.     

The effect of cholecystokinin peptides on ovine duodeno-jejunal slow waves with and without pretreatment with proglumide

Cholecystokinin exerts a composite influence on gastrointestinal motility but little is known about its effect on small-intestinal slow waves. Thus, six rams were implanted with four bipolar serosal electrodes onto the duodeno-jejunal wall. In the course of chronic experiments the myoelectric activity was continuously recorded in the non-fasted animals. After recording of the full normal migrating myoelectric complex (MMC), 0.15 M NaCl or CCK peptides were injected intravenously during various phases of the next MMC cycle. Five ml of saline was injected over 30 s during phases 1, 2a, or 2b of the MMC. Cerulein was administered at doses of 1 (over 30 s), 10 (over 30 or 60 s), or 100 ng/kg (over 30, 60, 120 or 300 s) and cholecystokinin octapeptide (CCK-OP) at doses 20 times higher. CCK peptides were applied during early or late phase 1 of the MMC and during phases 2a and 2b of the MMC. In the course of additional experiments, saline and hormone administration was directly preceded by infusion of proglumide, an unspecific CCK receptor antagonist, at a dose of 10 mg/kg. The myoelectric recordings were continued until the arrival of a subsequent regular phase 3 of the MMC. In the duodenal bulb, slow waves were occasionally observed. In the duodenum the slow-wave frequency oscillated between 20 and 24 cpm and in the jejunum between 19 and 22 cpm before or after CCK peptides and proglumide. In the duodenum the slow-wave amplitude increased significantly after all doses of cerulein injected during phase 2b of the MMC. After administration of CCK-OP changes in duodenal slow-wave amplitude were not significant but exhibited a tendency similar to those after cerulein. In the jejunum, injection of cerulein and CCK-OP during phase 2 of the MMC increased the slow-wave amplitude significantly and the duration of these changes was longer than in the duodenum. After infusion of proglumide, administration of cerulein at the low dose over 30 s and at the high dose over 300 s in the course of late phase 1 and phases 2a and 2b of the MMC, significantly increased the duodenal slow-wave amplitude. Cerulein injection during phase 2b of the MMC at the high dose over 30 and 60 s, preceded by proglumide infusion, significantly inhibited the duodenal slow-wave amplitude. In the jejunum these changes were even more pronounced and their duration was much longer. It is concluded that CCK peptides affect slow-wave amplitude in the duodeno-jejunum in non-fasted sheep. This effect is stronger in the jejunum and is altered but not abolished by pretreatment with proglumide. Cerulein evokes more pronounced alterations in the slow-wave amplitude than CCK-OP in conscious sheep.     

Effect of xylazine treatment on equine proximal gastrointestinal tract myoelectrical activity

Five 5 to 6 month old horses were surgically prepared with silver electrodes sutured to the serosa of gastric antrum, duodenum and proximal portions of the jejunum. Normal migrating motility complex (MMC) periodicity was determined during daytime hours in horses that were fed and horses from which food was withheld for 24 hours. Periodicity was defined as time span from the end of one period of regular spike activity (RSA) to the end of the next RSA in the MMC. The periodicity was 120.5 +/- 9.5 (SEM) minutes in horses from which food was withheld, and was 125.7 +/- 20.3 minutes in horses fed hay free choice. Coincident with each duodenal RSA, antral spike activity ceased. Xylazine (0.25 and 0.5 mg/kg), given IV during the period of intermittent spike activity of the MMC to either fed or unfed horses induced, within 2 minutes, a RSA complex in the duodenum that migrated to the proximal portion of the jejunum. This was followed by a period of no spike activity of normal duration, which proceeded on to a period of intermittent spike activity of varying duration to complete the MMC cycle. Pretreatment IV administration of an alpha 2-adrenergic antagonist, tolazoline (1 mg/kg) also provoked a RSA complex, but blocked the xylazine effect. The results indicated that xylazine resets the duodenal MMC in the horse, but does not seriously disrupt proximal gastrointestinal tract motility, and that control of MMC periodicity in this region probably involves more than alpha 2-adrenergic receptors.     

Comparison of ultrasonographic characteristics of the gastroduodenal junction during pyloroplasty performed laparoscopically or via conventional abdominal surgery in dogs

OBJECTIVE: To evaluate the use of ultrasonography to detect morphologic changes in the pylorus during pyloroplasty performed laparoscopically or via conventional abdominal surgery in dogs. ANIMALS: 10 healthy mixed-breed dogs. PROCEDURE: Laparoscopic ultrasonography of the pylorus was performed in 5 dogs during laparoscopic pyloroplasty (LP), and ultrasonography of the pylorus was performed in 5 dogs during pyloroplasty via conventional abdominal surgery (CAP group). Appearance and dimensions of the pyloric sphincter were evaluated by use of a 7.5-MHz flexible laparoscopic linear-transducer probe. RESULTS: Mean +/- SD duration of the ultrasonographic procedure was 11 +/- 3.04 minutes (range, 6 to 18 minutes). In the CAP group, cross-sectional views of the pylorus revealed significant differences between the overall transverse external diameter, overall craniocaudal external diameter, and transverse diameter of the pyloric lumen. After surgery, the pyloric area was significantly increased. Longitudinal views of the pylorus revealed that width of the pyloric ring was significantly less after surgery. Transverse views of the pylorus for the LP group revealed a significant increase in the transverse diameter and craniocaudal diameter of the pyloric lumen after LP. The pyloric area was also significantly increased after surgery. Longitudinal views of the pylorus revealed that width of the pyloric ring was significantly less after surgery. Transverse diameter of the pyloric lumen was significantly increased after LP. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of results of this study suggests that ultrasonography is useful for detecting relevant morphologic changes in the pyloric sphincter after pyloroplasty.     

Involvement of neuronal nitric oxide synthase (nNOS) in the regulation of migrating motor complex (MMC) in sheep

The objectives of this study were to evaluate the role of nitric oxide (NO) synthase isoforms (nNOS, eNOS, and iNOS) in the regulation of the migrating motor complex (MMC) in sheep using electromyography and their expression in the gastrointestinal (GI) tract by Western blot (WB) and immunohistochemistry. Intravenous administration of L-NAME or the nNOS inhibitor 7-nitroindazole (7-NI) decreased the MMC interval. Myoelectric activity of intestinal phase II was increased, whereas antral activity was reduced. These effects were blocked by L-arginine. Inhibitors of either iNOS (aminoguanidine and S-methylisothiourea) or eNOS (L-NIO) were ineffective. The NO donor sodium nitroprusside decreased GI myoelectric activity, inhibited the MMC pattern, and prevented the effects induced by L-NAME and 7-NI in the intestine. Intracerebroventricular administration of these agents did not modify GI motility. In the rumen, abomasal antrum, duodenum, and jejunum, WB showed three bands at about 155, 145, and 135kDa corresponding to nNOS, and a 140-kDa band (eNOS); however iNOS was not detected. Positive nNOS immunostaining was observed in neurons of the myenteric and submucous plexus of all GI tissues, while eNOS was found in the endothelial cells, ruminal and intestinal epithelium, as well as in some enteric neurons and in endocrine-like cells of the duodenal Brunner's glands. In contrast, only weak iNOS immunoreactivity was found in ruminal epithelium. Taken together, our results suggest that NO, synthesized at a peripheral level by nNOS, is tonically inhibiting the MMC pattern and intestinal motility in sheep.     

The prevalence and distribution of gastric ulceration in 345 racehorses

OBJECTIVE: To report the prevalence and distribution of gastric ulceration within a group of racehorses and to describe the endoscopic appearance of gastric antrum and pyloric ulceration. DESIGN: Retrospective clinical study. PROCEDURE: Medical records from gastroscopic examinations of 345 racehorses (331 Thoroughbreds and 14 Standardbreds) were reviewed. Prevalence, distribution and severity of gastric ulcers were recorded. Lesions involving the squamous mucosa and the glandular mucosa of the antrum and pylorus were graded and compared. RESULTS: Gastric ulceration was found in 86% of racehorses. The squamous mucosa around the margo plicatus was most commonly affected. The pylorus was examined in 175 horses and 47% were ulcerated. No association was found between presence of lesions of the squamous mucosa and those of the pylorus. Low correlation was found between grade and location of lesions, with the pyloric lesion score being significantly less than the squamous mucosal lesion score. CONCLUSION: Gastric ulceration was present in a large proportion of racehorses. The pylorus was also an important site of ulceration. There was no association between presence of lesion at one site and the other, although there was a low correlation between grade of lesion and location, with the pyloric ulcer grade being lower.     

Surgical Treatment of Gastric Outflow Obstruction in 40 Foals

Objective— To report short- and long-term survival and factors affecting outcome of foals after surgical correction of gastric outflow obstruction.
Study Design— Case series.
Animals— Foals (n=40) aged 5–180 days.
Methods— Clinical signs, laboratory data, diagnostic imaging, surgical findings, surgical procedures, medical treatment, and necropsy findings were retrieved from medical records. Outcome was obtained by reviewing performance, sales, and produce records or by telephone conversations with the owners.
Results— Gastric outflow obstruction was treated by gastroduodenostomy or by gastrojejunostomy with or without jejunojejunostomy. Long-term follow-up was available for 36 of 39 foals that survived to hospital discharge; 25 (69%) survived >2 years. All 8 foals with pyloric obstruction survived >2 years, whereas only 11 of 21 (52%) foals with duodenal obstruction survived >2 years. Six of 8 foals with obstruction of the duodenum and pylorus survived >2 years. Obstruction of the duodenum, adhesions to the duodenum, and postoperative ileus were significantly associated with decreased long-term survival.
Conclusions— Long-term outcome after gastric bypass procedures was substantially improved compared with previous reports. Factors that may have contributed to improved survival include better case selection and performing the gastrojejunostomy with the jejunum aligned from left to right.
Clinical Relevance— The prognosis for long-term survival after surgical bypass of pyloric obstruction is excellent. The overall prognosis for long-term survival after surgical bypass of duodenal obstruction is fair but should be considered guarded in those with pre-existing duodenal adhesions.     

Ultrasonographic characterization of the feline cardia and pylorus in 34 healthy cats and three abnormal cats

A prospective study was performed in 34 fasted healthy cats to describe the normal ultrasonographic anatomy of the cardia and pylorus. Measurements were obtained for the caudal esophageal wall thickness (Ew), cardia wall thickness (Cw), pyloric wall thickness (Pw), thickness of the pyloric muscularis (Mp), length of the thicker part of the proximal duodenal submucosa (Dl). Among the 34 cats, 24 were examined using a linear transducer, and 10 with a microconvex transducer. Ew and Cw could be measured in 70% of the cats when a linear transducer was used, in 100% of the cats when a microconvex probe was used, Pw and Mp could be measured in 100% of the cats whatever probe was used. The submucosa of the most proximal part of the duodenum was thicker in half of the cats in longitudinal section. The muscularis layer of the pylorus was triangular in longitudinal section and thicker than the muscularis of the proximal duodenum. The mean for Ew, Cw, Pw, Mp, and DI was 4.9 mm (SD = 1.1), 5 mm (SD = 0.6), 4.4 mm (SD = 0.6), 2.5 mm (SD = 0.5), and 4.7 mm (SD = 2.38), respectively. Three cats with abnormalities of the cardia and pylorus are also described to illustrate clinical implications.     

Intermittent gastric dilatation after gastropexy in a dog.

Gastroperitoneal adhesions, which developed after tube gastrostomy in a 3-year-old dog, caused an inverted L configuration of the pyloric antrum and duodenum, resulting in periodic episodes of gastric dilatation. The dog had undergone tube gastrostomy for treatment of gastric dilatation/volvulus, but gastropexy adhesions broke down 27 months later, necessitating a second pexy procedure. Adhesions then developed, constricting gastric outflow and trapping gas in the stomach and proximal duodenum. When the ventral row of adhesions was surgically dissected, the angle between the pyloric antrum and the duodenum was straightened, facilitating flow of digesta. Gastropexy rarely causes the degree of adhesion formation and the complications reported in this dog.     

Influence of deoxynivalenol on the D-glucose transport across the isolated epithelium of different intestinal segments of laying hens

Deoxynivalenol (DON) decreases glucose absorption in the proximal jejunum of laying hens in vitro and this effect is apparently mediated by the inhibition of the sodium D-glucose co-transporter. DON could modulate the sugar transport of other intestinal regions of chickens. For this purpose, we have measured the effects of DON on the Na(+) D-glucose co-transporter, by addition of DON after and before a glucose addition in the isolated epithelium from chicken duodenum, jejunum, ileum, caecum and colon by using the Ussing chamber technique in the voltage clamp technique. The data showed in all segments of the gut that the addition of D-glucose on the mucosal side produced an increase in the current (Isc) compared with the basal values, the Isc after glucose addition to the small intestine was greater than the Isc of the large intestine compared with the basal values, specially of the jejunum (p < 0.002), indicating that the jejunum is the segment that is the best prepared for Na(+)-D-glucose co-transport. Further addition of 10 microg DON/ml to the mucosal solution decreased the Isc in all segments and the Isc returned to the basal value, especially in the duodenum and mid jejunum (p < 0.05). In contrast, the addition of 5 mmol D-glucose/l on the mucosal side after incubation of the tissues with DON in all segments had no effect on the Isc (p > 0.05), suggesting that DON previously inhibited the Na(+)D-glucose co-transport. The blocking effects of DON in duodenum and jejunum were greater than the other regions of the gut. It can be concluded that the small intestine of laying hens has the most relevant role in the carrier mediated glucose transport and the large intestine, having non-significant capacity to transport sugars, appears to offer a minor contribution to glucose transport because the surface area is small. The effect of D-glucose on the Isc was reversed by DON in all segments, especially in the duodenum and jejunum, suggesting that DON entirely inhibited Na(+)-D-glucose co-transport. This finding indicates that the inhibition of Na(+) co-transport system in all segments could be an important mode of action for DON toxicity of hens.     

New approach to the fed pattern: feeding evokes the specific spike burst setting in the small bowel of non-fasted sheep

As feeding is not a factor disrupting the migrating motor (myoelectric) complex (MMC) in sheep, it is presumed that the fed pattern is absent in this animal species. In turn, feeding may stimulate ovine gastrointestinal motility. To verify this discrepancy the myoelectric activities of the antrum and duodeno-jejunum were recorded in seven adult sheep. Additionally, the relationship between electrical and mechanical activity was tested in four of these animals by means of strain gauge force transducers mounted near the duodenal electrodes. Chronic experiments were conducted in fasted and non-fasted sheep before, during, and after standard feeding. Fodder was offered during the duodenal phases 1, 2a, or 2b of the MMC. Two types of responses to feeding (an unspecific and a specific fed pattern) were denoted. A simple increase in spike burst intensity, i.e. without their special deployment and assessed as the myoelectric activity index (unspecific fed pattern), was observed in the abomasal antrum and small bowel during and after feeding in the course of phase 2b of the MMC in non-fasted and fasted sheep. In the abomasal antrum its duration was longer than in the small intestine. In non-fasted animals the unspecific fed pattern was more pronounced in the abomasal antrum than in the small bowel, while its duration was longer in fasted animals. The specific fed pattern was evoked in the duodeno-jejunum during feeding initiated in the course of phase 2b of the MMC exclusively in non-fasted animals. During this pattern, the spike burst series were significantly reduced compared with those which appeared during phase 2b of the MMC and dispersed single spike bursts predominated. The average duration of the specific fed pattern was 3-4 min and it arrived 2-7 min after feeding onset. In the remaining periods during feeding, the spike burst pattern resembled that often observed during phase 2b of the MMC. Thus the confined fed pattern is present in sheep and its character depends upon the gastrointestinal region and feeding habits.     

Preliminary study of capsule endoscopy in the small intestine of horses

Objective To evaluate the visibility of various portions of the small intestine in healthy horses using capsule endoscopy. Procedure Six healthy, conscious adult Thoroughbreds were restrained and an endoscopic capsule (PillCam® SB capsule) was inserted into the oesophagus using an intranasal catheter aided by a guide wire. Water (500 mL) flushed the capsule down the gastrointestinal tract. Data were collected and stored in the recorder of the endoscopic system for 6 hours after capsule insertion and the images were evaluated using an image reader and scored using a visual analogue scale. Results Capsule endoscopy enabled observation of the distinct mucosal shape, colour, and villus structure of the intestinal lumen from the duodenum through the proximal jejunum. At 4 h after passing the pylorus, the endoscopic capsule started transmitting increasingly dark images in the distal jejunum as the lumen circumference increased. Means of the visual analogue scale in the duodenum, proximal jejunum, and distal jejunum were 93.8 ± 1.3%, 86.2 ± 2.5% and 48.8 ± 6.3%, respectively. Differences among these values were statistically significant (P < 0.05). Conclusions and Clinical Relevance Capsule endoscopy enables observation of the distinct mucosal shape, colour and villus structure of the proximal and mid-small intestine in healthy horses.     

日粮对肉牛小肠pH值及淀粉酶活性的影响

本文对肉牛饲喂不同日粮（玉米秸,５０％玉米秸加５０％玉米面）后小肠不同部位（十二指肠、空肠和回肠）ｐＨ值及粉酶活性进行了测定。结果表明：肉牛小肠不同部位的ＰＨ值及淀粉酶活性不同,回肠ＰＨ值高于空肠,回肠和空肠ＰＨ值显著高于十二指肠（Ｐ〈０．０５）,喂５０％玉米秸加５０％玉米面日粮的牛小肠ＰＨ值低于喂养一玉米秸日粮;空肠淀粉酶活性高于回肠,空肠和回肠淀粉酶活性均显著高于十二指肠（Ｐ〈０．０５）,饲喂     

In vitro effects of erythromycin, lidocaine, and metoclopramide on smooth muscle from the pyloric antrum, proximal portion of the duodenum, and middle portion of the jejunum of horses

OBJECTIVE: To evaluate effects of erythromycin, lidocaine, and metoclopramide on smooth muscle of the pyloric antrum (PA), proximal portion of the duodenum (PD), and middle portion of the jejunum (MJ) of horses. Sample Population-Strips of smooth muscle from 7 horses. PROCEDURE: Isolated muscle strips were suspended in a bath and attached to isometric force transducers. Once stable spontaneous contractions were observed, agents were added. Isometric stress responses were compared with the amplitude of spontaneous contractions. RESULTS: A single dose of erythromycin to the PA increased contractile amplitude (CA) for the longitudinal smooth muscle (mean +/- SEM, 76+/-16 g/cm2) but decreased CA for circular smooth muscle (-79+/-23 g/cm2). The inhibitory effect was decreased by tetrodotoxin, N(G)-nitro-L-arginine methyl ester, and a vasoactive intestinal peptide antagonist. Erythromycin increased CA for the MJ, which was maximal at 10(-4)M (171+/-36 g/cm2). Lidocaine increased CA for the PD, which was maximal at 10(-4) M (60+/-5 g/cm2). Metoclopramide increased the CA, which was maximal at 10(-4) M for the PA (75+/-26 g/cm2), PD (279+/-33 g/cm2), and MJ (456+/-59 g/cm2). CONCLUSIONS: Regional differences in responses to erythromycin, lidocaine, and metoclopramide were evident in the gastrointestinal tract of horses. Metoclopramide increased CA in all tissues used, whereas erythromycin inhibited CA in circular smooth muscle but stimulated CA in longitudinal smooth muscle from the PA. Inhibition is caused by stimulation of inhibitory nerves and is mediated, in part, by nitric oxide and vasoactive intestinal peptide.     

Pyloric stenosis caused by hypertrophic gastritis in three dogs

Hypertrophic gastritis of the pyloric antrum is described in an 11-year-old female poodle, a 14-year-old male Maltese terrier and a 13-year-old male mongrel. The dogs suffered from chronic vomiting. Gastroscopic examination revealed mucosal proliferations in dogs 1 and 3. Radiographic examination showed signs of pyloric obstruction in all three dogs. Contrast studies demonstrated thickenings in the region of the pylorus in dogs 1 and 2. Laparotomy was done in all three dogs: in dog 1 a gastro-duodenostomy was performed and in dogs 2 and 3 the circularly thickened mucosa was resected. The mucosa of all three dogs showed hypertrophic gastritis, chiefly due to foveolar hyperplasia, and round cell infiltration, especially in the superficial layers. Herniation of mucosal glands through the muscularis mucosae was found in dog 1. Dogs 1 and 2 recovered well and vomiting ceased. Dog 3 continued to vomit because of a pyloric stenosis, mainly due to muscular hypertrophy.     

Effects of medetomidine on intestinal and colonic motility in the dog

The motor responses of the jejunum and colon to stimulation of α₂-adrenoceptors by medetomidine and clonidine were investigated in four dogs. In fasting dogs, medetomidine, at a dose rate of 30 μg/kg i.v., disrupted the migrating myoelectric complex (MMC) pattern of the small intestine for about 2 h. Similar, but shorter-lasting effects were also induced by clonidine (30 μg/kg i.v.) on the jejunum. The administration of α₂-agonists inhibited colonic motility in fasting dogs, although medetomidine-induced inhibition was preceded by a short period of increased muscle tone. All these effects were reversed by the α₂-antagonists atipamezole (0.15 mg/kg i.v.) and yohimbine (0.20 mg/kg i.v.). In fed dogs, medetomidine (30 μg/kg i.v.) induced a strong increase of the tone on the proximal colon, while the activity of the medium and distal colon was completely suppressed. Yohimbine (0.50 mg/kg i.v.) immediately restored the activity of the colon and induced a propagated giant contraction and defaecation by the animal. These data confirm the importance of a₂-adrenergic receptors in the control of intestinal and colonic motility in the dog.     

The effect of lidocaine on postoperative jejunal motility in normal horses

OBJECTIVE: To measure the effect of lidocaine on the duration of the migrating myoelectric complex (MMC) and Phases I, II, and III of the MMC, spiking activity of the jejunum, and number of Phase III events when administered postoperatively to normal horses. STUDY DESIGN: Nonrandomized cross-over design. METHODS: Horses were anesthetized and via flank laparotomy 4 silver-silver chloride bipolar electrodes were sutured to the proximal jejunum. Electrical activity was recorded for 6 hours during 3 recording sessions beginning 24, 48, and 72 hours postoperatively. Saline (0.9% NaCl) solution was administered for 3 hours followed by lidocaine administration for 3 hours (1.3 mg/kg bolus intravenously [IV], 0.05 mg/kg/min IV constant rate infusion). RESULTS: Duration of MMC was unchanged during lidocaine administration (77 minutes-saline versus 105 minutes-lidocaine, P=.16). Durations of Phase I and II were unchanged during lidocaine administration (P=.19 and .056, respectively). Phase III was shorter during lidocaine administration (P=.002). Spiking activity was unchanged at all time periods during lidocaine administration (24 hours-P=.10; 48 hours-P=.95; and 72 hours-P=.12). The number of Phase III events was unchanged over all time periods during lidocaine administration (P=.053). CONCLUSIONS: Duration of MMC, spiking activity, and number of Phase III events was unchanged during lidocaine administration. CLINICAL RELEVANCE: Use of lidocaine as a prokinetic agent cannot be supported by this study in normal horses; however, results may differ in clinically affected horses.