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[Studies on colonic motor correlates of spontaneous defecation in conscious dogs].

The colonic motilities during defecation were studied by means of extraluminal strain gauge force transducers in six conscious dogs. A set of eight transducers was implanted in each dog: one was on the terminal ileum and the remaining seven were on the whole length of the colon equidistantly. As Karaus & Sarna had already described in 1987, giant migrating contractions (GMC) that were initiated in the proximal colon and rapidly migrated caudad before defecation were reconfirmed also in this study to be motor equivalent of mass movements. Several new findings in addition were obtained. At spontaneous defecation, a reflex relaxation was always observed at the distal end of the colon. This colonic outlet relaxation (COR) usually occurred synchronously with the initiation of GMC at the proximal colon and lasted until GMC had arrived at the distal end. Evacuation of feces occurred during this COR. COR was not observed at defecation induced by neostigmine or prostaglandin F2 alpha. After bilateral pelvic nerve section, both GMC and COR were completely abolished. Instead, group of low amplitude caudad migrating contractions occurred at the proximal or middle colon and were followed by frequent evacuation of small amount of loose stools. COR was not observed at this type of defecation. It is suggested from this study that not only GMC but also COR are the essential motor correlates of spontaneous defecation. Both GMC and COR are under control of pelvic nerves.

Animals

Neuroleptic-induced emotional defecation: effects of pimozide and apomorphine.

Neuroleptics, such as haloperidol, have been found to produce dysphoria, anxiety and akathisia in humans. In animals, these effects have rarely been reported since the decreased movement produced by these drugs can confound the study of many behavioral indices of emotionality. In fact, most investigators have found a decrease in emotional defecation in rats given neuroleptics in novel environments, supporting their action as a major tranquilizer. We have found, however, that in rats a profound increase in emotional defecation can result from haloperidol administration in well habituated environments, such as the homecage. In male rats, defecation was measured for a one hour test period following various doses of the neuroleptic, pimozide, and the dopamine receptor agonist, apomorphine. Apomorphine and pimozide (a dopamine receptor antagonist) were both found to increase levels of fecal boli excretions. In addition, when apomorphine was combined with haloperidol, defecation levels were also increased suggesting that this phenomenon is not directly mediated by dopamine receptors. It is suggested that this drug-induced defecation is a consequence of the agent's interaction with the affective state of the animal, creating a dysphoric or anxious state in the animal.

Animals

Cardio-vascular events at defecation: are they unavoidable?

Cardio-vascular events at defecation are to a considerable degree the consequence of an unnatural (for a human being) seating defecation posture on a common toilet bowl or bed pan. The excessive straining expressed in intensively repeated Valsalva Maneuvers is needed for emptying the bowels in sitting position. The Valsalva Maneuver adversely affecting the cardio-vascular system is the causative factor of defecation syncope and death. The cardio-vascular system of a healthy man withstands the intensive and repeated straining at defecation, while the compromised cardio-vascular system may fail resulting in syncope or even death. The squatting defecation posture is associated with reduced amounts of straining and may prevent many of these tragic cases.

Cardiovascular Physiological Phenomena

Control of defecation in patients with spinal injuries by stimulation of sacral anterior nerve roots.

OBJECTIVE: To observe the effects of stimulation of the sacral anterior roots on anorectal and low colonic pressures and to programme implanted stimulators to produce defecation. DESIGN: Prospective study of 12 consecutive patients. SETTING: Spinal injuries unit and university gastrointestinal physiology department. PATIENTS: 12 Patients with complete supraconal spinal cord lesions. Their injuries had been sustained at least two years before the study. INTERVENTIONS: A Brindley-Finetech intradural sacral anterior root stimulator was implanted in all patients. Three months postoperatively the stimulator settings were adjusted after measurement of simultaneous anorectal and low colonic pressures. MAIN OUTCOME MEASURES: Full defecation. RESULTS: Six patients achieved complete rectal evacuation of faeces using the implant and subsequently did not require manual help for defecation. For all but one of the patients the total time taken to complete defecation was reduced, and all were free from constipation, the most prevalent gastrointestinal symptom in patients with spinal injuries. CONCLUSIONS: Sacral anterior root stimulators can be programmed to achieve complete unassisted defecation and can considerably improve the quality of life of patients with spinal injuries.

Adult

[An experimental study of the diurnal changes in colonic motility centering on defecation].

The following findings have been obtained as a result of making an assessment regarding the diurnal changes in colonic motility by means of continuous measurement of contractile waves by using strain gauge force transducers and roentgenographic observation in conscious dogs. 1. Before defecation, the contractile force of the wave was weak, frequency of its emergence was also small, and transfer of intestinal content was slow, showing decrease of colonic motility. 2. After defecation, the gradually increasing and decreasing contractile wave groups became clear, and the contractile force was intensified concurrently with increase of its emerging frequency. Transfer of intestinal content to the anal side was rapid, and recovery of colonic motility was observed. 3. The recovery of the colonic motility after defecation was observed regardless of digestive or interdigestive state. 4. By intake of food, increase of the colonic motility corresponding to gastrocolic response was observed, but it was due to the increase of emerging frequency of contractile wave, for which no change was observed in contractile force or duration in each individual waves. 5. It was suggested that the contractile motion which undergoes gradual increase and decrease is the basic pattern in the colonic motility and that the colonic motility changes by the differences of amount, shape and hardness of intestinal content, and decreases gradually along with increase of intestinal content, but the basic pattern of contractile motion is restored by inflow of intestinal content into the colon which became empty after defecation. From the above it was considered to be inadequate to use the pattern classification of digestive and interdigestive state for the analysis of colonic motility and that assessments should be made centering on defecation.

Animals

Observations on the feeding and defecation patterns of three triatomine species (Hemiptera: Reduviidae).

A comparative laboratory study of feeding and defecation behavior of three species of tritomines (Rhodnius prolixus, Triatoma infestans and T. dimidiata) indicated evident differences among the species and among the different stages of same species. Time required for a full blood meal was related to the size of the specimen. Insects required an average of 11-28 min for engorgement although some finished within 10 min. T. dimidata frequently interrupted the act of feeding, a probable explanation of the higher number of defecations before finishing a blood meal observed in the species. R. prolixus was superior to the other two species in number of defecating insects and in rapidity and frequency of defecations within a given time. T. dimidiata was inferior in all three parameters and T. infestans was intermediate. Males of all species tended to be less effective. A "defecation index" is proposed for comparing this different behavior in triatomine specimens under standard conditions. Effectivity of the insects according to the measured parameters is discussed in relation to the prevalence of Chagas' disease in those areas where they are principal vectors.

Animals

The effect of feeding on defecation behaviour in pigs.

The effect of eating on defecation behaviour was investigated in four 20-30 kg pigs. Rectal distention stimulation was performed pre- and postprandially at 10 cm from the anus with a 5 cm latex balloon. Volume was increased in steps of 10 ml up to 200 ml of air or until balloon defecation. Dependent measures were volume, rectal pressure, determined with a solid state pressure transducer inside the balloon probe, rectal compliance, and an index of distention induced contractile activity. The volume and pressure required to elicit defecation was significantly lower after feeding (p less than 0.01). Distention induced contractile activity was significantly increased near defecation threshold, but pre- and postprandial conditions were not different. There was no difference in rectal compliance pre- and postprandially. These results suggest that eating lowers defecation threshold in terms of distention volume and rectal pressure, and that these changes are not dependent on altered rectal compliance or changes in distention induced motor activity.

Animals

Self washout method for defecational complaints following low anterior rectal resection.

A self washout method was performed by ten patients who had defecational complaints following an anterior resection. A commercially available colostomy washout set was used for this procedure. When the patient sat down, the cone tip of the set was pressed into the anal canal by pushing the cone with the palm of the hand. The volume of water for irrigation used was 500 to 1000 ml and the subsequent defecation time was from 20 to 50 minutes. In all cases, the frequent urge to defecate disappeared and after normal defecational function had been recovered, the self washout was able to be discontinued.

Adult

Effects of neonatal castration and testosterone injection on adult open-field behaviour in rats with atypical sex difference in defecation.

In the open-field test, male rats usually defecate more and ambulate less than females. A strain was studied in which the males defecate less than females, while still ambulating less. Infants of this strain were castrated (males) or injected with testosterone propionate (females) and tested in the open field as adults. There were significant effects of these neonatal treatments on ambulation, but not on defecation, in contrast to previous reports for the latter measure in rats showing a sex difference in defecation taking the usual direction. It is suggested that absence of the usual direction of a sex difference normally under the developmental control of androgen may indicate a genotype which has escaped from such control. Finally, a number of 'sibling' effects' were observed, i.e. effects on the adult behaviour of the members of one sex in a litter produced by treatments administered in infancy to members of the other sex.

Animals

Impairment of defecation in young women with severe constipation.

Anorectal manometry, radiology, and tests of simulated defecation were carried out in 14 severely constipated young women and 29 age-matched controls. The resting anal sphincter pressures were reduced in the patients, but the squeeze pressures, rectoanal inhibitory reflex, and rectal pressures upon balloon distention were all normal. At rest, the anorectal angle was more obtuse in the constipated group, but there was no overall increase in perineal descent in constipated patients compared with controls. The presence of a balloon in the rectum and the onset of pain were perceived in constipated patients at volumes that were not significantly different from those in normal volunteers. Constipated patients, however, required higher rectal volumes to induce the desire to defecate and to stimulate regular rectal contractions. Constipated patients also found it more difficult to pass simulated stools from the rectum than the normal controls and, unlike most normal controls, failed to inhibit their external anal sphincter on attempted defecation. These findings suggest that young women with severe constipation have great difficulty initiating the coordinated set of events that constitute a normal defecation response.

Adolescent

alpha-MSH, MIF-I and melatonin: effects on novelty-induced defecation, plasma 11-OHCS and central catecholamines in rats.

The pituitary-hypothalamo-pineal complex involving MSH, MIF-I and melatonin has been strongly emphasized in the adaptive mechanism of the animal. A series of experiments was conducted to investigate the effects of alpha-MSH, MIF-I and melatonin on novelty-induced defecation, step-down activity, plasma 11-OHCS levels and whole brain DA and NE concentrations over days of novelty X drug treatment. alpha-MSH consistently enhanced and sustained novelty-induced defecation, increased plasma 11-OHCS levels in the resting intact rats and in the novelty exposed hypophysectomized (hypox) rats, and decreased brain DA and NE levels in intact, hypox and sham-hypox rats. MSH did not increase plasma 11-OHCS in intact and sham-hypox rats during exposure to novelty. MIF-I significantly habituated novelty-induced defecation and increased brain DA and NE levels over 5 days of drug X novelty treatment. Melatonin, on the other hand, inhibited novelty-induced defecation, decreased plasma 11-OHCS and increased brain DA level over 5 days of melatonin X novelty treatment. MSH, MIF-I or melatonin did not show any significant effect on the step-down activity of the rats. The results suggest the possibility that central CAs may be implicated in the behavioral changes observed after alpha-MSH, MIF-I and melatonin administration and in the interaction of the pituitary-hypothalamo-pineal complex involving MSH, MIF-I and melatonin.

11-Hydroxycorticosteroids

The defecation pattern and diet in patients with an ileum reservoir and anal anastomosis with a long efferent leg.

The dietary habits and defecation patterns of 12 patients were examined 8-34 months after total colectomy with mucosal proctectomy and the construction of an ileal reservoir attached to an anal anastomosis. The reservoir was provided with a long efferent leg (12 cm) through the anal canal. The patients were divided into two groups in accordance with the frequency of defecation--one with fewer than six defecations per 24 h and another with more than six defecations per 24 h. The fecal output, however, was not significantly different in the two groups. The fecal content of sodium and potassium was the same as in feces from conventional ileostomies. The dietary intake was insufficient in energy content, vitamins, minerals, and trace elements. Dietary supplement was recommended.

Adult

Rectopexy is an ineffective treatment for obstructed defecation.

The symptoms of obstructed defecation have been attributed to rectal intussusception, and thus rectopexy has been advocated in the surgical management. In this study, patients with obstructed defecation underwent manometry and proctography before and after rectopexy. Seventeen patients (16 females and one male, mean age 51.6 years) were studied. Eleven underwent anterior and posterior fixation of the rectum and six had posterior fixation only. Preoperatively five patients demonstrated rectoanal intussusceptions. Fifteen had significant pelvic descent. No significant change in maximum resting pressure, maximum voluntary contraction, pelvic descent, or anorectal angle was seen postoperatively. In the initial follow-up, many patients had significant amelioration of symptoms. However, on longer follow-up (mean 30.8 months) only two had long-term improvement. The remainder had a poor clinical result in spite of complete resolution of rectal intussusception. Many reported a worsening of symptoms as reflected by an increase in tenesmus and stool frequency. In the two cases with a satisfactory result, both could empty the rectum completely and demonstrated rectoanal intussusception on preoperative evacuation proctography. In those with poor results, four had complete emptying and three had rectoanal intussusception. In conclusion rectopexy is an ineffective treatment for obstructive defecation in most patients.

Adult

A combined electromyographic and cineradiologic investigation in patients with defecation disorders.

Records from 20 patients on whom defecography and electromyography were performed simultaneously because of defecation disorders were analyzed. According to the electromyographic investigation, the patients could be divided into three main groups: 1) normal sphincter reaction; 2) paradoxical sphincter reaction; and 3) combined reaction. Group A was characterized by a marked reduction of muscular activity during emptying and a pronounced closing reflex after emptying. This was followed by return of normal tonic activity. Patients in group B had no relaxation of the sphincters during emptying but a pronounced increased activity in the external sphincter and the puborectalis muscle. They also had severe emptying difficulties at defecography. No closing reflex was seen. In group C the electrical activity in the sphincters increased during moderate straining and when emptying was complete a clear closing reflex was seen. In this study, a dynamic visualization of the defecation together with a registration of electromyographic activity in the striated anal sphincters was performed. It was shown that patients with paradoxical sphincter reaction were lacking a closing reflex after emptying was complete. This has not been reported previously and is important evidence for the paradoxical defecation pattern. It was also shown that the patients with rectoceles had paradoxical sphincter reaction.

Adult

A concept of the anatomy of the anal sphincter mechanism and the physiology of defecation.

A review of the new concepts of the anatomy of the anal sphincter mechanism and the physiology of defecation is presented. The external sphincter is a triple-loop system; each loop can function as a separate sphincter through voluntary inhibition action and mechanical compression. Stress defecation resulting from internal sphincter damage is described. A new technique for repair of rectal incontinence is presented, which depends on inducing continence not only by mechanical compression, but also by voluntary inhibition. The mechanism of defecation and rectal continence is described and four types of incontinence presented. Also, the mechanism of both the levator dysfunction syndrome and prolapse is demonstrated and a technique of repair is presented. The study defines two types of rectal anomalies; suprahiatal and infrahiatal. The role of the embryonic anorectal sinus, anorectal band, and epithelial debris in the genesis of perirectal suppuration, chronic anal fissure, pruritus ani, and hemorrhoids is described. The communicating veins, identified between the hemorrhoidal and vesical plexuses, offer an explanation for the vague pathologic aspects of recurrent bacteriuria, urethral discharge, cervicitis, and vaginitis, and provide a proper line for their treatment. They also serve to perform a new radiographic technique--anal cystography--and to administer drugs, including chemotherapeutics, in the treatment of pelvic malignancies.

Anal Canal

Effects of MIF-I and melatonin on novelty-induced defecation and associated plasma 11-OHCS and brain catecholamines.

In two experiments the effects were investigated of MSH-inhibiting factor-I (MIF-I) and of Melatonin on step-down latencies, defection, plasma 11-OHCS levels, whole brain DA and whole brain NE concentrations on Days 1, 3 and 5 of novelty exposure. Treatment with MIF-I led to a significant habituation of novelty-induced defecation over 5 days, whereas plasma 11-OHCS level was reduced only on Day 1. The concentrations of whole brain DA and whole brain NE also showed a significant increase over days of MIF-I and novelty treatment. Melatonin treatment, on the other hand, significantly inhibited novelty-induced defecation and reduced plasma 11-OHCS level on Day 5 of novelty exposure. Melatonin treatment led to a significant increase of whole brain DA in animals exposed to novelty for 5 days. Neither MIF-I nor Melatonin was found to significantly affect the step-down activity of treated animals. The overall results suggested a possible relationship between novelty-induced defecation and brain DA levels of MIF-I and Melatonin treated animals.

11-Hydroxycorticosteroids

The effects of cocaine on multivariate locomotor behavior and defecation.

The present study utilized a multifactorial open-field analysis (Digiscan activity) to assess behavioral changes induced by various doses of cocaine known to stimulate locomotion. The measures that were implemented included ambulation, rearing, stereotypic behavior, rotational movements and changes in defecation levels. Thirty-two male Sprague-Dawley rats were habituated to Digiscan-16 Animal Activity Monitors (Omnitech Electronics, Columbus, OH) before being injected with 0.0, 10, 20 or 30 mg/kg cocaine. Rats were kept on a reversed light/dark schedule and tested in the middle of the dark cycle. It was found that cocaine consistently increased activity measures; most prominently affecting the rotational and ambulatory indices. Interestingly, this 'activity print' appeared to be dose-dependent and specific to cocaine. Open-field defecation levels were compared to home-cage levels as an additional behavioral correlate. Defecation decreased under all doses of cocaine as compared to control levels (saline injection). This result is attributed to cocaine's weakly sympathomimetic effect.

Animals

Anorectal function and defecation dynamics in patients with rectal prolapse.

Seven female patients with clinical rectal prolapse and nine healthy female control subjects were studied with anorectal manometry, external sphincter electromyography, and a saline continence test. Resting anal tone, maximum voluntary squeeze, and rectal functional capacity were significantly decreased in the rectal prolapse patients (p less than 0.02). During defecation attempts, external sphincter or pelvic floor electromyographic activity decreased in all of the control subjects, whereas six prolapse patients showed increased electromyographic activity and one had no change in activity (p less than 0.01). Continence to saline solution was also significantly impaired in prolapse patients (p less than 0.001). Postoperative studies in three patients who underwent repair revealed persistence of abnormal anorectal function and defecation dynamics. Patients with rectal prolapse have impaired resting and voluntary sphincter activity, decreased functional rectal capacity, and impaired continence. The failure of normal relaxation of the external sphincter or pelvic floor during defecation attempts, as demonstrated in the patients described herein, may contribute to the development of prolapse and denervation sphincter injury seen in such patients.

Anal Canal