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PubMed1975

Open-field behaviour of oestrous and dioestrous rats: evidence against an 'emotionality' interpretation.

Oestrous and dioestrous rats were observed during the initial 2 min of open-field exposure, and after a loud bell had sounded. Although defecation and ambulation showed characteristic difference between the two phases (less defecation and more ambulation at oestrus), other measures associated with emotional behaviour (latency to move from the wall, flight, and freezing to the bell) showed no differences. These findings supported Drewett's suggestion that open-field defecation and ambulation change with oestrous phase because of general metabolic changes and not as a result of 'emotionality' changes.

Animals↗
PubMed1981

Pontine reticular unit responses to pelvic nerve and colonic mechanical stimulation in the dog.

The role of pontine reticula units (PRU) responding to afferent impulses from the distal colon and anal mucosa was studied in dogs. The 465 PRU were classified into 4 groups on the basis of the pattern of discharge in response to afferent stimulation (AS) of rectal branches (RB) of the pelvic nerve: Group I (G-I) responded with a short burst (latency, 36 +/- 16 msec); G-II responded with an early short burst (latency, 41 +/- 21 msec), followed by a late long-lasting train of spikes (latency, 187 +/- 110 msec); and G-III responded with a long-lasting train of spikes (latency, 189 +/- 130 msec). G-IV had spontaneous discharges which were temporally inhibited by AS. G-II and G-III PRU showed remarkable facilitation similar to that of the long latency reflex discharges of RB. G-I PRU showed habituation. Most of G-II and G-III PRU discharged simultaneously with the reflex discharges of RB; these cause the contractions of defecation in the distal colon. In each group, 6.4 +/- 14.8% of PRU were reticulospinal units with descending axons running beyond the 1st lumbar segment of the spinal cord. It was concluded that the pontine defecation reflex center plays an essential role in defecating activity.

Afferent Pathways↗
PubMed1990

Antagonism of 8-OH-DPAT-induced behaviour in rats.

Selective activation of the 5-HT1A receptor induces lower lip retraction (LLR) in rats. 8-Hydroxy-dipropylamino tetralin (8-OH-DPAT)-induced LLR could not be antagonised by the 5-HT antagonists methysergide, metergoline or mesulergine. In fact, some 5-HT antagonists induced LLR. However, 8-OH-DPAT-induced LLR could be antagonised by pindolol, spiperone, spiroxatrine and NAN-190, but not by the beta 1-adrenoceptor antagonist metoprolol, the beta 2-adrenoceptor antagonist butoxamine or the dopamine antagonist haloperidol. This antagonism was competitive as the dose-response curve of 8-OH-DPAT was shifted to the right. Pindolol, spiperone, spiroxatrine and NAN-190 all have a high affinity for the 5-HT1A receptor. This indicates that blockade of 8-OH-DPAT-induced LLR is only possible by selective blockade of 5-HT1A receptors. A possible mechanism of action is discussed. The increased defecation induced by 8-OH-DPAT could be antagonised by pindolol and NAN-190. The effect of spiroxatrine and haloperidol on the 8-OH-DPAT-induced increase in defecation was bimodal: an increase after a low and a decrease after a high dose of 8-OH-DPAT. Metoprolol and butoxamine had no effect on the 8-OH-DPAT-induced increase in defecation, thereby excluding an influence of beta-adrenoceptors.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1990

The 'ileal brake' after ileal pouch-anal anastomosis.

The aim of this study was to assess if infusion of oleic acid into the ileal pouch would slow gastric emptying and small-bowel transit, delay defecation, and increase plasma levels of enteroglucagon, neurotensin, or peptide YY in patients with colectomy and ileal pouch-anal anastomosis. Eight subjects with chronic ulcerative colitis who had undergone the operation were studied on 2 consecutive days. On 1 day, saline (154 mM NaCl) was infused into the ileal pouch, and on the other day emulsified oleic acid (152 mM) was infused. The subjects ate a 300-kcal mixed meal containing liquid labelled with 99mTc-DTPA. To assess small-bowel transit concurrently with gastric emptying, a second marker, 111In-DTPA, was instilled through a tube into the duodenum at the end of the meal. Transit of both markers was monitored scintigraphically. Infusion of oleic acid into the ileal pouch slowed gastric emptying and small-bowel transit, and delayed the time to defecation compared with saline infusion. Neither the ileal pouch infusion alone or the meal alone altered plasma levels of enteroglucagon, neurotensin, or peptide YY, but the combination of the oleic acid infusion and the meal increased the levels of all 3 hormones. It was concluded that an "ileal brake" on gastrointestinal transit is functional following ileal pouch-anal anastomosis. Oleic acid placed into the ileal pouch slowed gastrointestinal transit and delayed defecation, effects which may have clinical application. The mechanism mediating the ileal brake may in part be hormonal.

Adult↗
PubMed1992

Arginine vasopressin inhibits phasic contractions and stimulates giant contractions in monkey colon.

Abdominal cramps and urgent defecation are common side effects of clinical doses of arginine vasopressin, indicating that the drug may have stimulating effects on colonic motor activity. Four strain-gauge transducers were implanted on the colon in six monkeys. A blood flow probe was fixed on the inferior mesenteric artery. After a 1-hour control recording, vasopressin, 0.13, 1.3, or 13.0 ng.kg-1.min-1, was infused intravenously for 90 minutes. The frequency of basal colonic contractions was reduced with increasing doses of vasopressin, but their mean amplitude and duration were not altered. Giant migrating contractions associated with defecation were initiated by the highest dose of vasopressin. Atropine had no effect on these giant migrating contractions but completely inhibited normal phasic contractions. Hexamethonium completely inhibited both giant migrating contractions and phasic contractions. Parasympathetic denervation of the colon did not inhibit giant migrating contractions initiated by vasopressin. Our findings suggest that the physiological concentrations of serum vasopressin present perioperatively may transiently inhibit spontaneous colon contractions but are unlikely to be the major cause of postoperative ileus. The giant migrating contractions initiated by vasopressin may account for the defecation associated with pharmacological doses of vasopressin. The initiation of giant migrating contractions by vasopressin may be mediated through a neural pathway.

Animals↗
PubMed1995

Anorectal function in patients with complete spinal transection before and after sacral posterior rhizotomy.

BACKGROUND/AIMS: The implantation of spinal stimulators to facilitate defecation in patients with complete spinal transection involves division of the posterior sacral nerve roots. The aim of this study was to investigate the role of spinal reflexes in anorectal function. METHODS: Anorectal manometry and electromyography were performed in 14 patients with supraconal spinal cord transection (C6-T12) before and after complete sacral posterior rhizotomy and in 30 normal controls. RESULTS: Patients with spinal transection lost conscious control of the external anal sphincter. Reflex responses to intra-abdominal pressure and to rectal distention were eliminated after rhizotomy, indicating that they are spinal reflexes. Rhizotomy also eliminated giant rectal contractions induced by rectal distention in these patients. In contrast, the exaggerated sphincter relaxation induced by rectal distention was not influenced by rhizotomy. Discriminant rectal sensation was lost, but patients with thoracic cord lesions perceived a dull pelvic sensation during rectal distention even after rhizotomy. CONCLUSIONS: The exaggerated anorectal smooth muscle responses and absent conscious control of the anorectum may explain why patients with complete spinal transection experience uncontrollable reflex defecation, and the persistence of external anal sphincter contraction during straining may impair fecal expulsion. The elimination of these responses after posterior rhizotomy prevented reflex defecation while facilitating manual evacuation.

Adult↗
PubMed1994

Cecocolonic motility in the chicken. Effects of cholecystokinin.

The aims of this work were 1) to define electromyographically the motility pattern of chicken ceca and colon; 2) to study the changes induced by photoperiod and food intake on the motility of this area and 3) to characterize the motor effects of intravenous (i.v.) cholecystokinin in vivo, measuring changes in electrical activity and intracecal pressure. Electromyographical studies show that in ceca, the spike burst frequency is higher during the day than during the night and in the fed than in the fasted state; about 90% of the bursts propagate towards the apex and corresponde to filling movements. In the colon the spike burst frequency during the day is 2.9 bursts/min in animals fed ad libitum. Nocturnal recordings in animals fed ad libitum and diurnal recordings in fasted animals show a significantly decreased electrical activity. Both CCK-8s and CCK-4 induce a dose-dependent decrease of colonic electrical activity and a dose-dependent increase in the number of colonic defecations. CCK-4 also causes a slight inhibition in the cecum, whereas CCK-8s induces an increase in cecal electrical activity. Intracecal pressure recordings performed in anaesthetized animals provide similar results. In conclusion, the cecocolonic motility of the chicken displays a circadian pattern and undergoes substantial modifications in the fed compared to the fasted state. CCK-8s is not mediating the increased colonic activity that follows food intake, as its effects on colonic motility are inhibitory. In contrast, i.v. CCK-8s induces defecation and a dose dependent increase in cecal electrical activity, intraluminal pressure and colonic defecation. Intravenous CCK-4 induces inhibitory effects both on ceca and colon.

Action Potentials↗
PubMed1991

Behavior and corticosteroid response of Maudsley reactive and nonreactive rats in the open field and forced swimming test.

Maudsley reactive (MR) and nonreactive (MNRA) male rats were tested in the open field and in the forced swimming test. MR rats defecated more and were less active than MNRA rats in the open field. MR rats also defecated more, but were more immobile in the forced swim test. The two strains did not differ significantly in basal corticosteroid levels or corticosteroid levels in response to either test. These results suggest that the increased defecation rates exhibited by MR rats in various tests are not indicative of a general increase in "emotionality" or stress level.

Animals↗
PubMed1992

Determinants of the slow acquisition of medical and sulcal prefrontal cortex self-stimulation: an individual differences approach.

Stimulation-naive rats were tested for motor activity during noncontingent electrical stimulation of the medial prefrontal cortex (MPC) or sulcal prefrontal cortex (SPC). Defecation during stimulation was also measured. The rats were then tested using a conditioned taste aversion paradigm for aversion to a novel flavor (0.1% saccharin) paired with stimulation. Finally, the rats were trained to acquire self-stimulation over 26 days of training. Large individual differences were seen in motor activity, defecation, and conditioned taste aversion to initial stimulation and in the subsequent speed of self-stimulation acquisition. In the MPC-stimulated group, acquisition speed was positively correlated with motor activity to initial stimulation and negatively correlated with defecation to this stimulation. In the SPC-stimulated group, the same correlations were evident, but only when rats suffering seizures prior to self-stimulation acquisition were excluded from the analysis. Such preacquisition seizures, which were only found in the SPC-stimulated group, retarded self-stimulation acquisition. In most rats, MPC or SPC stimulation failed to condition a taste aversion to saccharin. These results suggest that the slow acquisition of MPC and SPC self-stimulation may be partly related to the motor suppressive, aversive, and convulsive properties of initial stimulation.

Animals↗
PubMed1995

To drink or not to drink: open field behavior in alcohol-preferring and-nonpreferring rat strains.

High open field activity has been associated with high alcohol intake in inbred mouse strains. The present study sought to determine if a similar relationship might exist in rats. Strains which voluntarily drink large amounts of alcohol (alcohol-preferring [P], alcohol-accepting [AA], Fawn-Hooded [FH]) or little or no alcohol (alcohol-nonpreferring [NP], alcohol-nonaccepting [ANA], Flinders Resistant Line [FRL]) were compared with the Maudsley strains of rats selectively bred for differences in open field defecation and activity. There were highly significant strain differences in open field activity, with the alcohol-preferring P rats exhibiting the highest activity and the alcohol-nonpreferring Maudsley Reactive rats exhibiting the lowest. However, the NP rats were almost as active as the P rats and the AA and ANA rats exhibited intermediate levels of activity which did not differ from each other. Thus, there was no consistent relationship between open field activity and high voluntary alcohol intake. Defecation was highest in the Maudsley Reactive rats, and there was a consistent negative relationship with alcohol intake (r = -0.455 across all strains). In a population of 57 FHxFRL F2 hybrids, there were no significant correlations between alcohol intake and open field activity (r = -0.01) or defecation (r = +0.12). We conclude, therefore, that there was no consistent relationship between voluntary alcohol intake and open field behavior across strains of rats.

Alcohol Drinking↗
PubMed1994

Nutrient ingestion increases rectal sensitivity in humans.

To determine the effect of nutrient ingestion on rectal perception thresholds (first sensation, consistent urge to defecate, pain), rectosigmoid balloon distentions were performed with a computerized automated pump in eight healthy volunteers (four males, four females, 31.6 +/- 6.02 years). Two measurements of rectal balloon distention were performed on 2 separate days. Day 1 served as a control condition with no meal. On day 2 the subjects received a 600 kcal liquid meal. On the control day, determination of perception thresholds was performed two times with a 10-min break between measurements. On the experimental day, threshold determinations were made before and after the ingestion of the liquid standard meal. The order of the experimental days was counterbalanced. Distention volumes at the urge to defecate and the pain threshold (maximum tolerable volume) were significantly reduced following the meal. The average change from pre- to postprandial measurements of the threshold for urge to defecate was -20.55 +/- 4.22% and for the maximum tolerable volume it was -16.09 +/- 4.4%. These results extend data previously reported from animal studies using similar experimental methods.

Adult↗
PubMed1985

Measuring the anorectal angle.

Lateral radiographs of the rectum and anus were taken in 90 children with chronic idiopathic constipation. A computer program was developed to obtain an objective quantitative assessment of the anorectal angle; it averaged 120 degrees at rest, decreased during forceful anal contraction and increased during defecation. It was noted that 24% of the children, when asked to defecate, decreased their anorectal angle as normally observed during forceful anal contraction and, that 21% when asked to contract the anus, increased the angle as if they were defecating. This 'sphincteric disobedience' is probably of major clinical relevance to an understanding of the symptoms of these patients.

Adolescent↗
PubMed2004

Relationship between gastrointestinal transit time and daily stool frequency in patients after Ileal J pouch-anal anastomosis for ulcerative colitis.

BACKGROUND: To investigate how the gastrointestinal transit function changes after ileal J pouch-anal anastomosis (IPAA) for ulcerative colitis (UC) and to study whether gastrointestinal transit time (GTT) has an influence on daily stool frequency, we investigated the relationship between GTT and stool frequency per day. METHODS: Forty patients with UC who had undergone restorative proctocolectomy, with ileostomy closure at least 48 to 120 months (mean 96.3) previously, and who had no preoperative and postoperative complications were recruited. They were divided into two groups on the basis of their stool frequency: 26 patients had a stool frequency of less than 6 times per day (group A: 16 men, 10 women; aged 15 to 59 years old, average 36.6) and 14 patients had a stool frequency of 7 or more times per day (group B: 10 men, 4 women; 24 to 56 years old, average 40.9). The GTTs using a radiopaque marker were studied. Interviews concerning the defecation states were performed at the examination. RESULTS: High nocturnal stool frequency was significantly noted more in group B than in group A (P <0.001). All cases in group A and 12 cases in group B could discriminate flatus from feces, and there were significant differences between groups A and B (P <0.05). Feeling of stool remaining was significantly noted more in group B than in group A (P <0.01). Stool consistency in group A was harder than that in group B (P <0.001). Patients with soiling were significantly noted more in group B compared with those in group A (P <0.001). Incontinence was detected in only 2 cases in group B. Group A showed a better defecation state than group B. In the GTT study, the GTT was almost the same in groups A and B. The small bowel transit, pouch transit, and whole gut transit times in group B were faster than those of group A (P <0.001). Removal length of the terminal ileum in patients after IPAA: patients in group B (13.8 +/- 3.9 cm) had significantly more ileum removed compared with patients in group A (6.3 +/- 2.4 cm; P <0.001). Regression lines in the relationship between removal length of the terminal ileum and individual stool frequency showed there was a correlation between removal length of the terminal ileum and individual stool frequency per day in direct proportion (r = 0.79, P <0.001). A resection of more ileum, up to 15 cm, plays a role in increased stool frequency. CONCLUSIONS: The present results suggested that rapid transit of both the small bowel and pouch may lead to a high stool frequency of 7 or more times per day with a poor defecation state after IPAA. It was also pointed out in this study that an important point is a resection of more ileum, up to 15 cm, plays a role in increased stool frequency.

Adolescent↗
PubMed2005

The Rho/Rac-family guanine nucleotide exchange factor VAV-1 regulates rhythmic behaviors in C. elegans.

Rhythmic behaviors are a fundamental feature of all organisms. Pharyngeal pumping, the defecation cycle, and gonadal-sheath-cell contractions are three well-characterized rhythmic behaviors in the nematode C. elegans. The periodicities of the rhythms range from subsecond (pharynx) to seconds (gonadal sheath) to minutes (defecation). However, the molecular mechanisms underlying these rhythmic behaviors are not well understood. Here, we show that the C. elegans Rho/Rac-family guanine nucleotide exchange factor, VAV-1, which is homologous to the mammalian Vav proto-oncogene, has a crucial role in all three behaviors. vav-1 mutants die as larvae because VAV-1 function is required in the pharynx for synchronous contraction of the musculature. In addition, ovulation and the defecation cycle are abnormal and arrhythmic. We show that Rho/Rac-family GTPases and the signaling molecule inositol triphosphate (IP(3)) act downstream of VAV-1 signaling and that the VAV-1 pathway modulates rhythmic behaviors by dynamically regulating the concentration of intracellular Ca(2+).

Amino Acid Sequence↗
PubMed2006

The corner of the coloproctologist: what to ask to radiologist.

Defecation disorders, fecal incontinence, often associated to urinary and genital dysfunction, represent symptoms of a large number of functional and structural alterations of pelvic floor. They can be evaluated by functional and morphologic tests. A perfect anatomic and functional knowledge of the anorectum and pelvic floor is indispensable for a correct diagnostic and therapeutic path. Incontinence due to sphincter lesions can be diagnosed only by imaging techniques. In defecation disorders the issue is complex because functional and anatomic alterations can coexist. The radiological diagnosis of dyssynergic defecation is a diagnosis of confidence that enhances its value when manometric and electromyographic evidence of pelvic dyssynergia are detected. When anatomical alterations are detected the aim is to understand their physiopathology, to make a more precise diagnosis and treatment, and to minimize the errors of an inappropriate therapy. Our attention is focused on the information provided by imaging techniques about anorectum and pelvic floor abnormalities for optimal therapeutic planning.

Anal Canal↗
PubMedDate not supplied

Polyethylene glycol electrolyte solution (Isocolan) for constipation during pregnancy: an observational open-label study.

To evaluate the efficacy of a polyethylene glycol electrolyte solution (PEG-4000) in pregnant women affected by constipation, 40 consecutive pregnant women from 6 to 38 weeks' gestation were enrolled in this preliminary study. Constipation was defined as spontaneous evacuation less than four times a week or the presence of symptoms such as defecation pain, rectal urgency, tenesmus, anal injury, or abdominal pain. A PEG-4000 solution (Isocolan, also marketed in the United States as Golitely/Nulitely) was administered for 15 days at a dose of 250 mL by mouth once or twice a day. The number of bowel movements per week, the presence or absence of liquid stools, tenesmus, urgency, defecation pain, anal lesions, and abdominal pain were evaluated before and after 15 days of treatment. Treatment with PEG-4000 significantly increased the evacuation episodes per week (from 1.66 +/- 0.48 to 3.16 +/- 1.05; P <.01), and constipation was resolved in 27 of 37 women (73%). Defecation pain, anal injury, and abdominal pain significantly improved after PEG-4000 administration. Improvement occurred in both patients with new-onset constipation during pregnancy as well as patients with a history of constipation before pregnancy. These preliminary findings indicate that PEG-4000 may be an effective choice for the treatment of constipation during pregnancy.

Adult↗
PubMed2005

Long-term outcomes of a neo-anus with a pudendal nerve anastomosis contemporaneously reconstructed with an abdominoperineal excision of the rectum.

BACKGROUND: Pudendal nerve innervation can transform a neo-sphincter into an original anal sphincter-like muscle in animal studies. The results led us to clinical trials of a neo-anus with a pudendal nerve anastomosis (NAPNA). No long-term results in a series have been reported. METHODS: From 1995 to 2003, a neo-anus was reconstructed by using an inferior portion of the gluteus maximum muscle with a pudendal nerve anastomosis contemporaneously with an abdominoperineal excision of the rectum (APER) in 19 patients (17 men, 2 women; median age, 62.0 years; range, 46-73) with low-lying malignancy. The long-term (<2 years) clinical results were evaluated. RESULTS: The neo-sphincter began contracting (n = 15) at 6.6 +/- 1.8 months after surgery; then the ileostomy was closed (n = 14) at 9.1 +/- 2.6 months. The long-term results were studied in 10 patients (40.9 +/- 14.1 months after ileostomy closure). All patients (100%) defecated at 4.8 +/- 2.6 times/day without irrigation. Pads were used every day in 9 patients (90%). The Cleveland Clinic Florida incontinence score was 12.2 +/- 3.3 points. No patients lost their occupation. Eight patients (80%) answered that their life with a NAPNA was better than with an ileostomy. The average World Health Organization Quality of Life-BREF in patients with NAPNAs was significantly better than that in those patients who underwent conventional APERs in our hospital (n = 27, 66.4 +/- 0.8 years old) ( P = .0402). Four patients (40%) experiencing the need to defecate got significantly better continence score (mean +/- SD). CONCLUSIONS: The sensitivity to recognize the need to defecate may be a key to success in NAPNAs. A NAPNA can be a practical option for selected patients wishing to avoid a stoma after an APER.

Age Factors↗
PubMed1996

The ileocecal reservoir for rectal replacement in complicated radiation proctitis.

BACKGROUND/AIMS: Total rectal resection is the radical treatment method for radiation proctitis complications. Park's straight colo-anal reconstruction to replace the rectum often impairs anal continence, increases stool frequency, and causes imperative urgency. We developed and assessed a colo-anal reconstruction (ileocecal reservoir) after resection of radiation-damaged rectum. METHODS: An ileocecal segment was isolated on its lymphovascular pedicel, rotated counterclockwise, and reanastomosed at the dentate line. This provided a neorectal segment with intact intrinsic and extrinsic nerve and lymphovascular supply. We evaluated the safety, defecation quality, and anorectal function of this neorectum in two radiation-injured patients when compared with 15 patients after total mesorectal excision without radiation damage. RESULTS: No perioperative morbidity related to this technique was observed. Neorectal patients showed good defecation quality with maximal tolerable volumes, compliances, and anal manometry comparable with patients without radiation injury. CONCLUSIONS: This rectal replacement technique permits good defecation quality and excellent anorectal function.

Adult↗