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Biomedical subjects

J Fioramonti

Publications and source records attributed to J Fioramonti.

At least 163 records · Page 9Linked to original sources
PubMed1987

Action of T-2 toxin on gastrointestinal transit in mice: protective effect of an argillaceous compound.

Using sodium [51Cr]chromate as radiolabeled marker, gastrointestinal transit of a milk test meal was determined in mice receiving for 4 days T-2 toxin (1 mg/kg per day per os) alone or with a clay, smectite (2 g/kg per day), given according to four different procedures. Gastric emptying and small intestinal transit were significantly accelerated after the 1st T-2 administration and during the 4 days of treatment. When smectite was given together with the toxin with or without pretreatment by smectite alone for 2 days, the T-2 induced disturbances in gastrointestinal transit remained unchanged. A pretreatment by smectite for 4 days abolished the T-2 induced acceleration of gastric emptying but not of small intestinal transit. When T-2 was incubated with smectite for 24 h before oral administration, gastric emptying and small intestinal transit were not significantly accelerated.

Animals↗
PubMed1987

Colonic myoelectrical activity in IBS painless diarrhoea.

Colonic myoelectrical activity was recorded during 24 hours in 23 patients with painless diarrhoea and compared with a control group of 10 healthy subjects without digestive functional disorders. Diurnal fasting activity showed no significant difference in the total long spike bursts activity (LSB lasting greater than 7 seconds), but short spike bursts activity (SSB, lasting less than 7 seconds) was significantly lower (p less than 0.05) in diarrhoeal patients. A striking difference was observed in colonic response to eating, with an increased number of migrating long spike bursts (MLSB: mass movements) during the first postprandial hour in diarrhoeal patients (p less than 0.001), while short spike bursts (segmental activity) were almost absent in the rectosigmoid area. A marked decrease in the retrograde LSB activity was also observed in eight patients. During the night (from 2200 h to 0600 h) the number of migrating long spike bursts was increased in the diarrhoea group, but almost absent in controls (p less than 0.001). This study shows that colonic motor activity was altered in painless diarrhoea. These disturbances were not limited to the decreased SSB activity in the sigmoid, but involved the whole colon, with lower SSB activity and abnormal increase of migrating long spike bursts activity (MLSB) in postprandial and nocturnal periods.

Action Potentials↗
PubMed1987

Comparative influences of acoustic and cold stress on gastrointestinal transit in mice.

The effects of acoustic and cold stress on gastric emptying and intestinal transit were evaluated in mice treated with saline, diazepam, muscimol, propranolol, and naloxone using a radiolabeled chromium test meal. Acoustic stress (AS) was produced by playing music from a magnetic tape through loudspeakers (less than 86 dB) in a confined box at room temperature; and cold stress (CS) was produced by cold (10 degrees C) exposure. AS and CS sessions lasted 20 min. Both AS and CS were accompanied by a significant (P less than 0.05) increase in gastric emptying during at least 1 h. When measured 30 min after the meal, AS and CS increased gastric emptying from 43% of the test meal to 63 and 73%, respectively. Only CS affected intestinal transit, causing a 12.1% increase of the geometric center when measured 30 min after the test meal. Diazepam (0.5 mg/kg) muscimol (0.5 mg/kg), or propranolol (1 mg/kg) administered intraperitoneally reduced or abolished the effects of AS and CS on both gastric emptying and intestinal transit. In contrast naloxone (0.2 mg/kg im), which increased gastric emptying when injected alone, was unable to affect the AS-induced alterations of gastric emptying but partially reduced those of CS. Intracerebroventricular administration of corticotropin-releasing factor (250 ng/kg) also increased by 52.1% the gastric emptying, whereas the geometric center was not affected. It is concluded that both AS and CS accelerate gastric emptying in mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Changes in gastro-intestinal motility induced by cholera toxin and experimental osmotic diarrhoea in dogs: effects of treatment with an argillaceous compound.

Effects on digestive motility of two agents which induce diarrhoea were investigated in conscious dogs chronically fitted with strain-gauge transducers sutured to the serosa of the antrum, the jejunum and the proximal colon and with a catheter inserted into the duodenum. Effects were tested before, during and after treatment with an argillaceous compound, smectite, at a dose of 100 mg/kg/day for 6 days. Smectite treatment alone induced only minor changes in gastric motility with a decrease in the motility index and an increase in the duration of the post-prandial disruption of gastric migrating motor complexes (MMCs). Intraduodenal administration of cholera toxin (200 micrograms) before smectite treatment disrupted MMCs on the stomach and the jejunum for more than 10 h without affecting colonic motility. These effects were still seen when cholera toxin was administered on the 3rd day of smectite treatment but were partially antagonized on the 6th day of treatment. Intraduodenal infusion of a hypertonic mannitol solution (900 mosm/l, 6 ml/min for 1 h) transiently disrupted gastric and jejunal MMCs, stimulating colonic motility for more than 6 h and inducing abundant diarrhoea 45-60 min after the beginning of the infusion. When the mannitol infusion was repeated on the 3rd and 6th days of smectite, gastric and jejunal motor disturbances persisted while colonic hyperactivity was abolished and onset of diarrhoea was delayed by more than 8 h. We thus conclude that smectite treatment has an antidiarrhoeal effect, partially antagonizing digestive motor disturbances induced by two agents used to provoke experimental diarrhoea.

Animals↗
PubMed1987

Effects of loperamide hydrochloride on experimental diarrhea and gastrointestinal myoelectrical activity in calves.

The antidiarrheal action of loperamide hydrochloride was tested against diarrhea experimentally induced in calves by intraduodenal infusion of castor oil or hypertonic solution of mannitol. The motility of 4 levels of the digestive tract (abomasum, jejunum, and proximal and spiral loops of the colon) was concomitantly recorded, using an electromyographic technique. Loperamide hydrochloride given per os at 0.4 mg/kg or intraduodenally or subcutaneously at 0.1 mg/kg 1 hour before mannitol or castor oil was given delayed diarrhea. Loperamide hydrochloride given alone orally at a dosage of 0.4 mg/kg did not modify the motility pattern of the digestive tract. Intraduodenally administered loperamide hydrochloride (0.1 mg/kg) increased the frequency of the cyclic activity of the jejunum, whereas subcutaneously administered loperamide hydrochloride at the same dose selectively inhibited the motility of the jejunum. Intraduodenal infusion of mannitol was followed by a disruption of the cyclic activity of the jejunum, and this effect was not antagonized by loperamide hydrochloride, whatever the route of administration. Castor oil infusion was not accompanied with changes in gastrointestinal motility. These results indicate that loperamide hydrochloride is active against an experimentally induced diarrhea in calves and that this action is not mediated through an effect on the digestive motility, at least monitored by this electromyographic technique.

Abomasum↗
PubMed1986

A tetrapeptide isolated from hamster embryo with central opiate properties on gastrointestinal motility but not on pain perception.

The effects of centrally administered kentsin (H-Thr-Pro-Arg-Lys-OH) on intestinal motility and on pain perception were investigated in rats chronically equipped with lateral ventricle catheters. Intestinal motility was recorded electromyographically from electrodes placed on the duodeno-jejunum; analgesia was evaluated by the hot-plate and tail-flick tests. Kentsin (4.0 ug/kg), injected intracerebroventricularly (ICV) 2 hours after the beginning of a meal, restores the "fasted" i.e. the migrating myoelectric complex of intestinal motility, while a 5 times higher dose administered subcutaneously was inactive. The ICV effect of kentsin was blocked by previous ICV administration of naloxone (400 ug/kg). In contrast, kentsin administered ICV (40 ug/kg) or SC (200 ug/kg) did not affect significantly (P greater than 0.05) the time latency in the two analgesic tests during 90 minutes after its administration and did not significantly modify the analgesic effects of (D5-Ala2, Met5) enkephalinamide. We conclude that kentsin when centrally administered acts on opiate receptors to alter gastrointestinal motility but without effects on pain perception.

Animals↗
PubMed1986

Central regulation of intestinal basal and stimulated water and ion transport by endogenous opiates in dogs.

The influence of intracerebroventricular (ICV) vs intravenous (IV) administration of (D-Ala2, Met5) enkephalinamide (Dalamide) on normal and stimulated (cholera toxin) jejunal fluxes of water, Na+, and K+ were investigated in dogs prepared with a Thiry-Vella (TV) loop. Intestinal transport in the TV loop and concomitant transit time were measured during an infusion (2 ml/min) of an isotonic electrolyte solution alone, or containing 0.4 micrograms/ml of cholera toxin (CT). Basal net water absorption was slightly, but significantly (P less than 0.05), increased during an ICV infusion of Dalamide at 0.5 ng/kg/min, while the secretory effects of cholera toxin were markedly reduced by nearly 75%. Similar effects were observed for Na+ and K+ movement. In contrast, Dalamide infused intravenously at a five times higher dose, ie, 2.5 ng/kg/min did not affect the control and CT-stimulated water and electrolyte movements. The jejunal loop transit times were halved during CT infusion. Similar values were observed under Dalamide ICV administration as well as during a five times higher dose of Dalamide administered intravenously. It was concluded that (1) Dalamide administered into the CNS, but not peripherally, increased the absorption of water, Na+, and K+, causing a net reduction in their secretion induced by cholera toxin; and (2) these effects did not result from changes in transit time. These results also suggest that Met-enkephalin can act in the brain to affect the intestinal transport of water and electrolytes in dogs.

Animals↗
PubMed1986

Central alpha 2-adrenergic control of the pattern of small intestinal motility in rats.

The effects of central and peripheral administration of alpha 2-adrenoceptor agonists and antagonists on small intestinal motility were examined in conscious rats chronically fitted with electrodes implanted in the duodenojejunal wall and a cannula placed in a cerebral lateral ventricle. In fasted rats, intracerebroventricular or intraperitoneal administration of clonidine (5 micrograms) immediately disrupted the migrating myoelectric complex pattern with a total inhibition of spiking activity during the first hour, followed by a period of irregular spiking activity for 2 h. The inhibition was abolished by previous intramuscular administration of yohimbine (600 micrograms), and the period of irregular activity was suppressed by intracerebroventricular yohimbine (30 micrograms). Naphazoline, an alpha 2-agonist that poorly crosses the blood-brain barrier, only inhibited spiking activity when administered intraperitoneally (1 microgram) and induced only a period of irregular spiking activity when administered intracerebroventricularly at the same dose. In fed rats, intracerebroventricular administration of yohimbine or phentolamine (30 micrograms), and to a lesser extent prazosin, restores a migrating myoelectric complex pattern typical of the fasted state. Peripheral administration of these three antagonists at a dose 20 times higher was ineffective. Finally, both feeding and central administration of alpha 2-agonists disrupt the migrating myoelectric complex pattern. Such pharmacologic data suggest a possible role of central alpha 2-adrenoceptors in the regulation of intestinal motility in rats.

Animals↗
PubMed1986

Effects of corticotropin-releasing factor on plasma motilin and somatostatin levels and gastrointestinal motility in dogs.

The effects of intracerebroventricular and intravenous administration of corticotropin-releasing factor (CRF) on gastrointestinal motility, motilin-induced gastric motor response, and plasma motilin and somatostatin levels were investigated in fasted dogs chronically prepared with strain gauge transducers on the antrum and proximal jejunum. Administered intracerebroventricularly at doses of 20 and 100 ng/kg in fasted dogs, CRF suppressed for 4-5 h the gastric cyclic migrating motor complex. A similar dose (100 ng/kg) administered intravenously was inactive. Corticotropin-releasing factor administration by the intravenous route at 100 ng/kg did not alter the cyclic plasma motilin and somatostatin variations associated with the cyclic gastric motor events. During the blockade of antral migrating motor complex induced by intracerebroventricular administration of CRF, cyclic peaks of plasma motilin were absent whereas those of somatostatin persisted. The gastrointestinal migrating motor complex induced by the intravenous administration of porcine motilin (0.25 microgram/kg) was abolished when motilin was injected 2 h after the intravenous administration of CRF (100 ng/kg), whereas a similar dose of CRF administered intracerebroventricularly did not abolish the antral and jejunal motor responses to motilin. It is concluded that in fasted dogs, CRF administered centrally affects the interdigestive gastric motility and the release of motilin but not that of somatostatin. These results also suggest that the intracerebroventricular CRF-induced blockade of motilin release is responsible for the inhibition of gastric migrating motor complex and circulating CRF is able to affect the gastric motor response to porcine motilin through a peripheral mechanism that does not involve somatostatin and motilin secretion.

Animals↗
PubMed1986

The use of a compact protable microcomputer system (EPSON HX 20) to measure on-line the contractile activity of the digestive tract from eight channels. Application to pharmacological tests.

The chronically prepared gut with strain-gauge transducers is a useful model to evaluate the effects of drugs affecting the digestive motility in fed and fasted animals. This paper describes a rapid and reproducible on-line microcomputerized technique to evaluate continuously, 23 hr per day, the level of gut motility using a portable compact microcomputer (EPSON HX 20). The gastric, intestinal, and colonic motility indexes were automatically determined from the surface of the contractile waves from eight different sites over periods of time varying from 1 to 120 min. This system has been successfully used to investigate the motor effects of spasmolytic or antidiarrheal drugs inravenously (N-butyl-hyoscine, trospium, secoverine, and prifinium) or orally (trimebutine, loperamide) administered in conscious, fed dogs.

Animals↗
PubMed1985

Different targets for i.v. vs. i.c.v. administered morphine for its effect on colonic motility in dogs.

The effects of intracerebroventricular (i.c.v.) or intravenous (i.v.) administration of morphine on colonic motility were investigated in conscious dogs chronically fitted with a strain gauge transducer sutured to the serosa of the proximal colon. Morphine administered i.v. (100 micrograms/kg) or i.c.v. (10 micrograms/kg) induced similar increases in the motility index for about 3 h. The pattern of colonic contractions after i.v. morphine mainly consisted of an increase in the number of phases of contractile activity each lasting about 5 min. Morphine i.c.v. administered induced a peculiar pattern consisting of short (0.5-1.5 min) phases of contractile waves occurring at a high rate (10-15 per h). The effects of i.v. morphine were abolished after previous i.v. (1 microgram/kg) or i.c.v. (0.1 micrograms/kg) administration of naloxone or methyl-levallorphan, a narcotic antagonist with a high peripheral selectivity (100 micrograms/kg i.v., 10 micrograms/kg i.c.v.). The effects of i.c.v. morphine were not modified by previous i.v. or i.c.v. administration of naloxone (100 micrograms/kg). These results suggest that the stimulatory effect of i.v. morphine on colonic motility involves both central and peripheral components. The i.c.v. administration of morphine does not reproduce its central effect when given i.v. but acts on different central receptors.

Animals↗
PubMed1985

Central opioid-like influence of a tetrapeptide from hamster embryo (kentsin) on gastrointestinal motility in dogs.

The effects of intracerebroventricular (i.c.v.) vs. intravenous (i.v.) administration of kentsin (H-Thr-Pro-Arg-Lys-OH) on gastrointestinal motility were investigated in fasted dogs. Administered i.c.v. at doses of 20 and 100 ng/kg, this peptide inhibited by 51.2 and 76.1% the antral motility index and disrupted the jejunal migrating motor complex for 2 and 4 h respectively. Similar effects were only obtained after a 25 fold higher dose administered i.v. and these effects were abolished after a previous i.c.v. administration of naloxone (50 micrograms/kg) suggesting that they are mediated through opiate receptors.

Animals↗
PubMed1985

Enhancement of colonic motor response to feeding by central endogenous opiates in the dog.

The role of endogenous opiates in the colonic motor response to feeding has been investigated in four dogs chronically fitted with two strain gages on the proximal and distal colon and a cannula in cerebral lateral ventricle. A daily meal stimulated the colonic motility during 8-10 hrs. The colonic motility index was significantly higher during this period when an enkephalinase inhibitor, tiorphan, was intracerebroventricularly (i.c.v.) administered at a dose of 0.1 mg/kg before the meal. This effect was blocked by a previous i.c.v. administration of naltrexone (0.1 mg/kg) and reproduced by (D-Ala2, Met5) enkephalinamide (DALAMIDE) at a dose of 50 mg/kg. I.c.v. administration of tiorphan or DALAMIDE did not modify the colonic motility in dogs fasted for 48 hrs. The postprandial motility index remained unchanged after intravenous administration of tiorphan or DALAMIDE at the same dosages. These results provide evidence for a central control of the colonic motor response to feeding by endogenous enkephalins in dogs.

Animals↗