Comparative effects of mu and kappa opiate agonists on the cecocolic motility in the pony.

The electrical and mechanical activity of the large intestine and its response to administration of opiate mu and kappa agonists were assessed from electrodes and inductograph coils chronically implanted on the cecocolic segment in six ponies given a diet of hay and concentrates. Before the drugs were given, migrating complexes propagating from the cecum into the colon occurred at the rate of 1.5 to 16/hour.

Duodenal pH dips as an index of transpyloric flow in conscious dogs.

Background: To determine if duodenal pH fluctuations might be used as a valuable index of the occurrence of gastric chyme ejection, the transpyloric flow and pH in the duodenal bulb were monitored simultaneously in six dogs.

Methods: Transpyloric flow, monitored by a chronically implanted electromagnetic flowmeter, was represented by individual pulses of flow. Relations between the volume of these flow pulses and changes in duodenal pH were assessed both postprandially and during the increased gastric outflow that followed gastric loading of buffered saline solutions at pH 2 and 4.

Central and peripheral motor effects of galanin on the duodenojejunum and colon in fed rats.

The effects of intraperitoneal, intrathecal and intracerebroventricular injections of the peptide galanin (GAL) on duodenojejunal and colonic motility were studied in conscious fed rats. At 0.3-3.

Alterations of intestinal microflora by antibiotics. Effects on fecal excretion, transit time, and colonic motility in rats.

The effects of intragastric antibiotics in rats were examined on fecal microflora and excretion and through transit time and cecocolonic myoelectric activity. A solution of nonabsorbable antibiotics infused into the stomach for 20 days had a dramatic effect on the quantity, composition, and bacterial content of rat feces. Both the dry weight and the water content of feces were increased.

Relationships between pressure and flow across the gastroduodenal junction in dogs.

Antroduodenal pressure events were measured simultaneously with transpyloric flow, in conscious dogs, to evaluate the role of mechanical factors modulating this flow. The relationships between pressure and flow across the gastroduodenal junction were never linear. During the interdigestive state, terminal antral contraction occurred 0.

[Emptying of the abomasum in adult ruminants].

In the adult ruminant, abomasal emptying is a permanent phenomenon depending upon meal volume. Intradian rhythm involving the motor pattern of the duodenum and circadian rhythm of unknown origin modulate the transpyloric flow rate. The fundic tone, antro-duodenal coordination and pyloric resistance regulate gastric outflow.

On the relevance of non-steroidal anti-inflammatory drugs in the prevention of paralytic ileus in rodents.

In the mouse, the gastrointestinal transit of a charcoal marker, halved following the intraperitoneal administration of acetic acid, was no longer inhibited after pretreatment with the non-steroidal anti-inflammatory drugs (NSAIDs), indomethacin, ketoprofen, piroxicam or ximoprofen (0.25-2.5 mg kg-1 orally).

Hyperphagia induced by pylorectomy in sheep.

In the hay-fed sheep, gastric (abomasal) contents are delivered continuously into the duodenal bulb at a mean flow rate of 210 ml per hour. The pylorus could behave as the site of origin of a feedback satiety signal by acting as a distal stomach sphincter limiting the abomasal emptying rate. This ability of the pyloric sphincter was confirmed by enhancement of abomasal outflow following either pylorectomy or pyloroplasty.

Duodenal bulb control of the flow rate of digesta in the fasted and fed dog.

1. Continuous measurement of the flow of digesta near the pylorus, and 5 cm aborally, was assessed in the conscious dog using a chronically implanted flowmeter. The patterns of flow were related to motor activity of the gastroduodenal junction.

[Measurement of changes in parietal tonus of the abomasum in sheep].

An inflatable bag of 250 ml at the pressure of 2 mm Hg inside the abomasal lumen was used to identify the abomasal smooth muscle tone. Reduced tone of the ovine abomasum was assessed, like for the fundic part of the canine stomach, in relation with the cyclic motor activity of the proximal duodenum. Opposite effects were obtained following parasympathomimetic drug injection versus peptides of the gastrin group, suggesting a high responsiveness of the abomasal smooth muscle tone to both neural and hormonal influences.

Flow and passage rate studies at the ileal level in the rabbit.

Six female rabbits fitted with a simple glass cannula in terminal ileum and a further 6 non-cannulated rabbits were used to perform digesta flow and transit measurements. The animals received ad libitum a diet based mainly on lucerne meal. Flow and transit measurements were carried out using two particulate markers: ytterbium (Yb) fixed on lucerne meal cell-walls by soaking, and chromium (Cr) fixed by mordancing.

Involvement of serotonergic mechanisms in the disruption of ovine duodenal migrating myoelectric complex cycles by duodenal acidification.

Infusions of 1 and 4 mmol of HCl (pH 2.0) into the duodenal bulb of conscious sheep, within 30% of the period of the migrating myoelectric complex (MMC) cycle, induced aborally propagated premature phases of regular spiking activity (RSA) on the proximal duodenum. A transient inhibition of reticular contractions and a shortening of the period of subsequent duodenal MMC cycles were obtained with infusions of 4 mmol of HCl but not with infusions of 1 mmol.

Prokinetic effects of cisapride, naloxone and parasympathetic stimulation at the equine ileo-caeco-colonic junction.

The electromyogram of the terminal ileum, the caecum and the proximal right ventral colon was recorded in fasted conscious ponies receiving intravenously equiactive doses of pilocarpine (0.05 mg/kg) and carbachol (0.01 mg/kg) as acetylcholine analogues; cisapride (0.

Effects of intraluminal nutrients on intestinal myoelectric activity in rabbits.

In the unanesthetized rabbit, intraluminal infusions of D- and L-methionine, L-tryptophan, D-glucose, D-xylose, and lactulose had a biphasic effect on small intestinal myoelectric activity. A phase of enhanced activity was followed by a phase of inhibition. The excitatory phase was mimicked by saline solutions equiosmolar to the test solutions.

Gastroduodenal motor activity associated with gastric emptying rate in sheep.

1. Gastric emptying rate was calculated from dye dilution and was measured as the net flow over periods of 5 days through an electromagnetic probe inserted into a T-cannula, 5 cm beyond the pylorus in conscious hay-fed sheep. The net aboral flow was related to the motor activity of the antrum and duodenal bulb which was recorded via chronically fixed strain-gauge transducers.

Milk feeding and xylazine treatment induce increased antroduodenal motility in young cattle with opposite effects on duodenal digesta flow rate.

Antroduodenal myoelectrical activity and duodenal digesta flow rate in young cattle were assessed by implanted nichrome wire electrodes and reentrant duodenal cannulation with interposed flow-meter. In addition, a small glass electrode was inserted through a duodenal cannula to continuously measure the pH of duodenal contents. When eating only hay ad libitum, the duodenal myoelectrical activity showed the usual migrating myoelectrical complex (MMC) pattern.

[Masticatory cycles of the rumination type in vagotomized lambs].

Contractions of the fluid-filled RR dependent upon the activity of the myenteric plexus were observed within 2 weeks after vagotomy in sheep maintained on a liquid diet. Spontaneous but not adrenergic evoked rumination was recorded beyond the 5th week after vagotomy. The observation of ruminating-like activity during 120 to 200 min per day in chronically-vagotomized sheep indicates that the onset of rumination does not require a gastric afferent pathway.

Babesia major: abomasal transmural potential difference, and antroduodenal motility changes associated with experimental infection in calf.

Transmural potential difference, pH and ionic concentrations of the abomasal contents were measured in three calves. Antroduodenal motor patterns were recorded using electrodes and strain-gauge transducers fixed on the antrum and the duodenum. The calves were infected with 8 x 10(9) Babesia major intravenously and a significant drop in transmural potential difference, concomitant with a steady increase in Na+ and K+ concentrations of the abomasal contents occurred within 2 days.

Colonic alpha 2-adrenoceptor-mediated responses in the pony.

The motor responses of the caecum and colon to stimulation of alpha 2-adrenoceptors by xylazine and detomidine at the recommended dose levels of 0.6 and 0.1 mg/kg were investigated in three ponies.

Pharmacological modulation of postprandial colonic motor activity in the pony.

The contractile activity of the equine large intestine exhibited a biphasic response to feeding: enhancement of migrating complexes passing along the colon and an increase of 50% in cyclic variations in smooth muscle at intervals of 20 min on the left ventral colon for a period of 5 to 7 h postfeeding. The cholinergic agonist, bethanechol (50 micrograms/kg subcutaneously), induced both the migrating complexes and the cyclic variations at intervals of 10-15 min. In contrast, the intra-arterial infusion of PGF2 alpha (3 micrograms/kg/min) increased the contractile activity during infusion, but without inducing distinct patterns of activity.

Early myoelectrical activity changes during gastric or duodenal ulceration in dogs.

Antroduodenal myoelectric activity and gastric transmural potential difference were recorded before and during fundic, antral, or duodenal ulceration in dogs. Gastric injury was obtained by electrocoagulation of the fundic or antral mucosa. Duodenal ulceration was induced by cysteamine injection which was accompanied by nausea or vomiting.