Sennosides do not kill myenteric neurons in the colon of the rat or mouse

Results of medical treatment with psyllium, lactobacillus, and tryptophan (Plurilac® Trio) in obstructive defecation syndrome

INTRODUCTION

The term "obstructive defecation syndrome" (ODS) describes a complex condition characterized by defecatory disorders. Such a condition represents a significant proportion of patients, which is estimated to be up to 30% of patients affected by chronic constipation. Presently, a broad agreement has been reached on diagnostic studies, whereas the choice of treatment that aims to improve the quality of life and/or correct the prevalent abnormalities or all anatomical abnormalities remains controversial.

METHODS

This was a retrospective cohort study on 174 patients out of a total of 232 with ODS who were observed in a specialized university unit of surgical coloproctology between 2018 and 2022. Clinical assessment included examining the values of the Agachan-Wexner constipation score and Patient Assessment of Constipation (PAC)-quality of life (QoL) scores, a full digital anorectal examination, anoscopy, RX defecography, and a urogynecological consultation; a functional anorectal test, an endoanal ultrasound, and colonoscopy were performed in select patients. The patients were reevaluated after an 8-10-week course of medical treatment based on a high-fiber diet and fluid intake and 6 g of psyllium combined with lactobacillus and tryptophan b.i.d. The results were analyzed by means of the Wilcoxon rank-sum test, comparing pretreatment scores with the results at the first follow-up visit.

RESULTS

After 8-10 weeks of conservative treatment, 128 patients declared full satisfaction, 29 reported moderate satisfaction, and 17 (9.7%) declared no improvement. Among these 17, there were 5 patients with paradoxical puborectal contractions. The value of the Agachan-Wexner constipation score after treatment decreased from the pretreatment Agachan-Wexner constipation score mean value of 23.4 ± 3.7 (mean ± SD range 15-27) to a mean value of 5.3 ± 0.7 (range 3-8, p < 0.001). The quality of life improved, as shown by the PAC-QoL score, indicating great improvement in social relationships.

CONCLUSIONS

Given the benefits of conservative therapies, they represent a cornerstone in the treatment of ODS, a complex disorder. Diet and bulking agents are mandatory forms of treatment prior to making any surgical attempt, also considering the fact that the psychosomatic component of ODS is an essential prerequisite to match patient expectations.

A Retrospective Real-World Observational Study Assessing the Evolution of Bisacodyl Prescriptions in Patients with Constipation During Long-Term Treatment

BACKGROUND

Potential habituation could be a safety concern associated with the long-term use of bisacodyl in patients with constipation.

OBJECTIVE

In this study, we evaluated whether patients with constipation who require long-term treatment with bisacodyl will remain on a stable dose when treated for ≥ 28 days.

METHODS

In this retrospective, population-based, observational cohort study, electronic medical record data of adult patients with constipation between January 1, 2011, and December 31, 2019, were collected from The Health Improvement Network French database. Total bisacodyl exposure during the long-term (≥ 28 days) and follow-up (12 months) periods was evaluated. The primary endpoint was the dose change status of bisacodyl during the follow-up period from the initial dose in the long-term cohort.

RESULTS

Out of 5725 bisacodyl users in the database, 218 patients qualified to be part of the long-term cohort. A total of 166 (76.1%), 37 (17%), and 15 (6.9%) patients were initiated on bisacodyl at 5, 7.5, and 10 mg, respectively. During the follow-up, most (94%) of the patients remained on the same dose as initially prescribed for the first year. In contrast, only seven (3.2%) patients had their dose increased (from the initial prescribed dose of 5 mg), and the remaining six (2.8%) patients decreased their dose (four patients from the 7.5 mg group and two from the 10 mg group).

CONCLUSION

Bisacodyl can be prescribed at a stable dose for > 28 days as most patients remained on their initial prescribed dose during the follow-up period. No signs of habituation were observed in this real-world study.

Bisacodyl: A review of pharmacology and clinical evidence to guide use in clinical practice in patients with constipation

BACKGROUND

Bisacodyl is a member of the diphenylmethane family and is considered to be a stimulant laxative. It has a dual prokinetic and secretory action and needs to be converted into the active metabolite bis-(p-hydroxyphenyl)-pyridyl-2-methane (BHPM) in the gut to achieve the desired laxative effect. Bisacodyl acts locally in the large bowel by directly enhancing the motility, reducing transit time, and increasing the water content of the stool. A recent network meta-analysis concluded that bisacodyl showed similar efficacy to prucalopride, lubiprostone, linaclotide, tegaserod, velusetrag, elobixibat, and sodium picosulfate for the primary endpoint of ≥3 complete spontaneous bowel movements (CSBM)/week and an increase of ≥1 CSBM/week over baseline. The meta-analysis also found that bisacodyl may be superior to the other laxatives for the secondary endpoint of change from baseline in the number of spontaneous bowel movements per week in patients with chronic constipation. This observation stimulated the authors to review the available literature on bisacodyl, which has been available on the market since the 1950 s.

PURPOSE

The aim of the current review was to provide an overview of the historic background, structure, function, and mechanism of action of bisacodyl. Additionally, we discuss the important features and studies for bisacodyl to understand its peculiar characteristics and guide its use in clinical practice, but also stimulate research on open questions.

Functional Constipation: Individualising Assessment and Treatment

Chronic constipation is one of the five most common symptoms seen by gastroenterologist. In the absence of alarm symptoms, a confident symptom-based diagnosis can often be made using the Rome criteria. Three different subtypes have been identified to date: normal transit constipation, defaecatory disorders and slow transit constipation. Differentiation between these subtypes can be made through functional testing using tests such as anorectal manometry with balloon expulsion and a radio-opaque marker test. In general, patients are initially advised to increase their fluid and fibre intake. When these general lifestyle recommendations do not improve patients' symptoms, a step-wise and add-on treatment approach should be applied. This review summarises the diagnostic criteria to differentiate functional constipation from other causes of chronic constipation. In addition, current drug treatment options, including discussion of new therapeutic targets are discussed. Further, practical treatment approaches (choice and dosing), include discussion of combination/augmentation, treatment failure (adherence/expectations), and relapse prevention are mentioned. Finally, treatment and management of pain and bloating aspects are included.

The management of adult patients with severe chronic small intestinal dysmotility

Adult patients with severe chronic small intestinal dysmotility are not uncommon and can be difficult to manage. This guideline gives an outline of how to make the diagnosis. It discusses factors which contribute to or cause a picture of severe chronic intestinal dysmotility (eg, obstruction, functional gastrointestinal disorders, drugs, psychosocial issues and malnutrition). It gives management guidelines for patients with an enteric myopathy or neuropathy including the use of enteral and parenteral nutrition.

Evaluation and Treatment of Constipation in the Geriatric Population

Chronic constipation affects one-third of the US population and occurs disproportionately in the elderly and female individuals, increasing in older individuals who are institutionalized. This condition has a significant impact on health care costs and quality of life. Clinicians need to consider primary as well as secondary causes of constipation in elderly individuals because the cause is often multifactorial. Diagnostic algorithms should eliminate red-flag symptoms that may indicate a malignancy but also consider pelvic floor dysfunction, which is more common in this age group. An appropriate treatment plan is tailored to the severity of the patient's symptoms.

Chronic Constipation

Constipation is a common symptom that may be primary (idiopathic or functional) or associated with a number of disorders or medications. Although most constipation is self-managed by patients, 22% seek health care, mostly to primary care physicians (>50%) and gastroenterologists (14%), resulting in large expenditures for diagnostic testing and treatments. There is strong evidence that stimulant and osmotic laxatives, intestinal secretagogues, and peripherally restricted μ-opiate antagonists are effective and safe; the lattermost drugs are a major advance for managing opioid-induced constipation. Constipation that is refractory to available laxatives should be evaluated for defecatory disorders and slow-transit constipation using studies of anorectal function and colonic transit. Defecatory disorders are often responsive to biofeedback therapies, whereas slow-transit constipation may require surgical intervention in selected patients. Both efficacy and cost should guide the choice of treatment for functional constipation and opiate-induced constipation. Currently, no studies have compared inexpensive laxatives with newer drugs that work by other mechanisms.

Clinical utility of plecanatide in the treatment of chronic idiopathic constipation

Constipation is an important health burden that reduces the quality of life for countless millions of people. Symptom-centric therapeutics are often used to treat constipation due to unknown etiology, but in many cases, these drugs are either inadequate or have significant side effects. More recently, synthetic peptide agonists for epithelial guanylyl cyclase C (GC-C) have been developed which are effective at treating constipation in a sub-population of adult constipation patients. The first to market was linaclotide that is structurally related to the diarrheagenic enterotoxin, but this was followed by plecanatide, which more closely resembles endogenous uroguanylin. Both the drugs exhibit almost identical clinical efficacy in about 20% of patients, with diarrhea being a common side effect. Despite the potential for reduced side effects with plecanatide, detailed analysis suggests that clinically, they are very similar. Ongoing clinical and preclinical studies with these drugs suggest that treating constipation might be the tip of the iceberg in terms of clinical utility. The expression of cGMP signaling components could be diagnostic for functional bowel disorders, and increasing cGMP using GC-C agonists or phosphodiesterase inhibitors has huge potential for treating enteric pain, ulcerative colitis, and for the chemoprevention of colorectal cancer.

Effectiveness of senna vs polyethylene glycol as laxative therapy in children with constipation related to anorectal malformation

PURPOSE

Constipation is present in 80% of children with corrected anorectal malformations, usually associated to rectal dilation and hypomotility. Osmotic laxatives are routinely used for idiopathic constipation. Senna is a stimulant laxative that produces contractions improving colonic motility without affecting the stool consistency. We designed this trial to study the effectiveness of Senna versus polyethylene glycol for the treatment of constipation in children with anorectal malformation.

METHODS

A randomized controlled crossover design clinical trial, including a washout period, was conducted, including children with corrected anorectal malformations with fecal continence and constipation. The sample size was calculated for proportions (n=28) according to available data for Senna. Effectiveness of laxative therapy was measured with a three variable construct: 1) daily bowel movement, 2) fecal soiling, 3) a "clean" abdominal x-ray. Data analysis included descriptive statistics and a Fisher's exact test for the outcome variable (effectiveness).

RESULTS

The study was terminated early because the interim analysis showed a clear benefit toward Senna (p = 0.026). The sample showed a normal statistical distribution for the variables age and presence of megarectum. The maximum daily dose of Senna (sennosides A and B) was 38.7mg and 17g for polyethylene glycol. No adverse effects were identified.

CONCLUSION

Therapy with Senna should be the laxative treatment of choice as part of a bowel management program in children with repaired anorectal malformations and constipation, since the stimulation of colonic propulsion waves could lead to stool evacuation without modification of its consistency which can affect fecal continence.

LEVEL OF EVIDENCE

I - randomized controlled trial with adequate statistical power.

Systematic review of stimulant and nonstimulant laxatives for the treatment of functional constipation

BACKGROUND

Constipation is an uncomfortable and common condition that affects many, irrespective of age. Since 1500 BC and before, health care practitioners have provided treatments and prevention strategies to patients for chronic constipation despite the significant variation in both medical and personal perceptions of the condition.

OBJECTIVE

To review relevant research evidence from clinical studies investigating the efficacy and safety of commercially available pharmacological laxatives in Canada, with emphasis on studies adopting the Rome criteria for defining functional constipation.

SEARCH METHODS

PubMed, Medline, Embase and Evidence-Based Medicine Reviews databases were searched for blinded or randomized clinical trials and meta-analyses assessing the efficacy of nonstimulant and stimulant laxatives for the treatment of functional constipation.

RESULTS

A total of 19 clinical studies and four meta-analyses were retrieved and abstracted regarding study design, participants, interventions and outcomes. The majority of studies focused on polyethylene glycol compared with placebo. Both nonstimulant and stimulant laxatives provided better relief of constipation symptoms than placebo according to both objective and subjective measures. Only one study compared the efficacy of a nonstimulant versus a stimulant laxative, while only two reported changes in quality of life. All studies reported minor side effects due to laxative use, regardless of treatment duration, which ranged from one week to one year. Laxatives were well tolerated by both adults and children.

Emerging Pharmacologic Therapies for Constipation-predominant Irritable Bowel Syndrome and Chronic Constipation

Irritable bowel syndrome with constipation and chronic functional constipation are common digestive disorders that negatively impact quality of life and account for billions of dollars in health care costs. Related to the heterogeneity of pathogenesis that underlie these disorders and the failure of symptoms to reliably predict underlying pathophysiology, traditional therapies provide relief to only a subset of affected individuals. The evidence surrounding new and emerging pharmacologic treatments, which include both luminally and systemically acting drugs, is discussed here. These include agents such as lubiprostone, bile acid modulations, guanylate cyclase-C receptor agonists, serotonin receptor modulators and herbal therapies.

Is senna laxative use associated to cathartic colon, genotoxicity, or carcinogenicity?

Due to their natural origin, apparent low oral toxicity, effectiveness, and accessibility without a medical prescription, the anthranoid laxatives are a popular remedy for constipation and are frequently used abusively. Therefore, it is important to characterize its harmful and/or toxic effects. The sennosides, main active metabolites of senna, exhibit a very low toxicity in rats, and its genotoxic activity in bacterial strains as well as mammal cells was classified as weak in those cases where it was shown to be significant. The toxicological and mutagenic status of the crude extract of senna, however, is not as well characterized, and it is necessary to do so since it is frequently, and at the same time incorrectly, believed that the chronic use of anthranoid laxatives is a risk factor for the development of colorectal cancer. The objective of this article was to review the information that arises in various scientific medical databases using key words such as senna, sen, Senna alexandrina, Cassia angustifolia, sennosides, laxative toxicity, mainly ISI and non-ISI articles of journals with an editorial committee. Web pages of products or companies that publicize or commercialize this type of laxative were not included. This analysis establishes that (1) there is no convincing evidence that the chronic use of senna has, as a consequence, a structural and/or functional alteration of the enteric nerves or the smooth intestinal muscle, (2) there is no relation between long-term administration of a senna extract and the appearance of gastrointestinal tumors or any other type in rats, (3) senna is not carcinogenic in rats even after a two-year daily dose of up to 300 mg/kg/day, and (4) the current evidence does not show that there is a genotoxic risk for patients who take laxatives containing senna extracts or sennosides.

Constipation

Chronic constipation is a common disorder manifested by a variety of symptoms. Assessments of colonic transit and anorectal functions are used to categorize constipated patients into three groups, i.e., normal transit or irritable bowel syndrome, pelvic floor dysfunction (i.e., functional defaecatory disorders) and slow transit constipation. 'Slow transit' constipation is a clinical syndrome attributed to ineffective colonic propulsion and/or increased resistance to propagation of colonic contents. Defaecatory disorders are caused by insufficient relaxation of the pelvic floor muscles or a failure to generate adequate propulsive forces during defaecation. Colonic transit is often delayed in patients with functional defaecatory disorders. Normal and slow transit constipation are generally managed with medications; surgery is necessary for a minority of patients with slow transit constipation. Functional defaecatory disorders are primarily treated with pelvic floor retraining using biofeedback therapy.

Is pseudomelanosis coli a marker of colonic neuropathy in severely constipated patients?

AIMS

To study relationships between the number of pseudomelanosis coli cells and that of colonic enteric neurons and interstitial cells of Cajal, which are significantly reduced compared with controls in severely constipated patients. Pseudomelanosis coli is frequent in patients using anthraquinone laxatives. It is not known whether the prolonged use of these compounds damages the enteric nervous system in constipated patients.

PATIENTS AND METHODS

The relationship between the number of pseudomelanosis coli cells and that of colonic enteric neurons (as well as that of apoptotic enteric neurons) and of interstitial cells of Cajal was assessed by histological and immunohistochemical methods in 16 patients with chronic use of anthraquinone laxatives undergoing surgery for severe constipation unresponsive to medical treatment. No relationship was found between the number of pseudomelanosis coli cells and that of enteric neurons (and that of the apoptotic ones), nor of interstitial cells of Cajal, in either the submucosal or the myenteric plexus.

CONCLUSION

The use of anthraquinone laxatives, leading to the appearance of pseudomelanosis coli, is probably not related to the abnormalities of the enteric nervous system found in severely constipated patients.

An oral carcinogenicity and toxicity study of senna (Tinnevelly senna fruits) in the rat

Senna (Tinnevelly senna fruits), a known laxative derived from plants, was administered by gavage to Sprague-Dawley (Crl:CD (SD) BR) rats once daily at dose levels of 0, 25, 100 and 300 mg/kg/day for up to 104 consecutive weeks. Based upon clinical signs related to the laxation effect of senna, the highest dose (300 mg/kg/day) was considered to be a maximum tolerated dose. Sixty animals per sex were assigned to the control and dose groups. Assessments included clinical chemistry, hematology, full histology (control and high-dose groups; in addition, low and mid dose: intestinal tract, adrenals, liver, kidneys, brain and gross lesions) and toxicokinetics. The primary treatment-related clinical observation was mucoid feces seen at 300 mg/kg/day. When compared to controls, animals administered 300 mg/kg/day had slightly reduced body weights, increased water consumption and notable changes in electrolytes in serum (increases in potassium and chloride) and urine (decreases in sodium, potassium and chloride). The changes in electrolytes are most likely physiologic adaptations to the laxative effect of senna. At necropsy, dark discoloration of the kidneys was observed in animals in all treated groups. Histological changes were seen in the kidneys of animals from all treated groups and included slight to moderate tubular basophilia and tubular pigment deposits. In addition, for all treated groups, minimal to slight hyperplasia was evident in the colon and cecum. These histological changes, together with the changes seen in the evaluation of clinical chemistry and urine parameters, have been shown to be reversible in a previous 13-week rat study of senna. No treatment-related neoplastic changes were observed in any of the examined organs. Based upon these data, it is concluded that senna is not carcinogenic even after daily administration for 2 years at dosages of up to 300 mg/kg/day in Sprague-Dawley rats.

Treatment of Severe and Intractable Constipation

A careful clinical evaluation, exclusion of secondary causes (eg, colonic obstruction, metabolic conditions, and drug-induced constipation), and assessments of colonic transit and rectal evacuation are necessary to ascertain whether constipation is attributable to normal colonic transit, delayed colonic transit (ie, slow-transit constipation), or a rectal evacuation disorder (with or without delayed colonic transit). Idiopathic slow-transit constipation is a clinical syndrome predominantly affecting women and is characterized by intractable constipation and delayed colonic transit. This syndrome is attributed to disordered colonic motor function and spans a spectrum of variable severity ranging from patients who have relatively mild delays in transit, but are otherwise indistinguishable from irritable bowel syndrome, at one extreme to patients with colonic inertia or chronic megacolon at the other extreme. Most patients are treated with one or more pharmacological agent. A subtotal colectomy is effective and occasionally indicated for patients with medically refractory severe slow-transit constipation, provided that pelvic floor dysfunction has been excluded or treated. Pelvic floor dysfunction can be diagnosed by the clinical features and anorectal testing. Most patients with pelvic floor dysfunction will respond to pelvic floor retraining by biofeedback therapy.

Effects of long-term administration of Senna occidentalis seeds in the large bowel of rats

Plants of the genus Senna that contain anthranoides derivatives are frequently used as cathartics. Radiological studies have demonstrated that patients with chronic constipation who have used stimulant laxative have colonic redundancy and dilatation more frequently than patients who have not. The objective of the present work was to study morphological and histochemical changes of the lower gut after administration of Senna occidentalis seeds for a long period to rats, as observed in skeletal muscle fibers. Fragments of the lower gut of young and adult rats treated with S. occidentalis seeds (2% for 171 days and 3% for 61 days in the diet) were submitted to histological and histochemical analysis and to densitometry. The most important finding was decreased oxidative enzyme activity in smooth muscle cells and in myenteric neurons of the large bowel. As oxidative metabolism is essential for ATP and energy production, these results suggest that the functional intestinal disturbance caused by the chronic use of Senna occidentalis as a laxative can be due to a metabolic effect involving energy production, which would decrease colonic motility and cause functional colonic dilatation, but without any irreversible anatomic change.

N/A

N/A

Pan-colonic decrease in interstitial cells of Cajal in patients with slow transit constipation

BACKGROUND

Interstitial cells of Cajal (ICC) are required for normal intestinal motility. ICC are found throughout the human colon and are decreased in the sigmoid colon of patients with slow transit constipation.

AIMS

The aims of this study were to determine the normal distribution of ICC within the human colon and to determine if ICC are decreased throughout the colon in slow transit constipation.

PATIENTS

The caecum, ascending, transverse, and sigmoid colons from six patients with slow transit constipation and colonic tissue from patients with resected colon cancer were used for this study.

METHODS

ICC cells were identified with a polyclonal antibody to c-Kit, serial 0.5 microm sections were obtained by confocal microscopy, and three dimensional software was employed to reconstruct the entire thickness of the colonic muscularis propria and submucosa.

RESULTS

ICC were located within both the longitudinal and circular muscle layers. Two networks of ICC were identified, one in the myenteric plexus region and another, less defined network, in the submucosal border. Caecum, ascending colon, transverse colon, and sigmoid colon displayed similar ICC volumes. ICC volume was significantly lower in the slow transit constipation patients across all colonic regions.

CONCLUSIONS

The data suggest that ICC distribution is relatively uniform throughout the human colon and that decreased ICC volume is pan-colonic in idiopathic slow transit constipation.

Slow-transit Constipation

Idiopathic slow-transit constipation is a clinical syndrome predominantly affecting women, characterized by intractable constipation and delayed colonic transit. This syndrome is attributed to disordered colonic motor function. The disorder spans a spectrum of variable severity, ranging from patients who have relatively mild delays in transit but are otherwise indistinguishable from irritable bowel syndrome to patients with colonic inertia or chronic megacolon. The diagnosis is made after excluding colonic obstruction, metabolic disorders (hypothyroidism, hypercalcemia), drug-induced constipation, and pelvic floor dysfunction (as discussed by Wald ). Most patients are treated with one or more pharmacologic agents, including dietary fiber supplementation, saline laxatives (milk of magnesia), osmotic agents (lactulose, sorbitol, and polyethylene glycol 3350), and stimulant laxatives (bisacodyl and glycerol). A subtotal colectomy is effective and occasionally is indicated for patients with medically refractory, severe slow-transit constipation, provided pelvic floor dysfunction has been excluded or treated.

Slow transit constipation

Slow transit constipation is a clinical syndrome predominantly affecting young women, characterized by constipation and delayed colonic transit, occasionally associated with pelvic floor dysfunction. The disorder spans a spectrum of variable severity, ranging from patients who have relatively mild delays in transit but who are otherwise indistinguishable from irritable bowel syndrome patients at one extreme, to patients with colonic inertia or chronic megacolon at the other extreme. Potential mechanisms for impaired colonic propulsion include fewer colonic HAPCs or a reduced colonic contractile response to a meal. The cause of the syndrome is unclear. The treatment is primarily medical; surgery is reserved for patients with severe disease or colonic inertia. Recognition and treatment of pelvic floor dysfunction is crucial for patients treated medically or surgically. Collaborative studies are necessary to determine the pathophysiology of this disorder and to ascertain the efficacy of novel prokinetic agents.

AGA technical review on constipation. American Gastroenterological Association

This literature review and the recommendations therein were prepared for the American Gastroenterological Association Clinical Practice and Practice Economics Committee. The paper was approved by the Committee on March 4, 2000, and by the AGA Governing Board on May 21, 2000.

Review article: anthranoid laxatives and their potential carcinogenic effects

Anthranoid laxatives are widely used laxatives of natural origin. Because of their chemical structure they are carried unabsorbed to the large bowel, where metabolism to the active aglycones takes place. These aglycones exert their laxative effect by damaging epithelial cells, which leads directly and indirectly to changes in absorption, secretion and motility. Damaged epithelial cells can be found as apoptotic bodies in the pigmented colonic mucosa, characteristic for pseudomelanosis coli. Pseudomelanosis coli is a condition caused by chronic (ab)use of anthranoid laxatives and has recently been associated with an increased risk of colorectal carcinoma. In vitro and animal studies have shown a potential role of anthranoid laxatives in both the initiation and promotion of tumorigenesis. Studies in humans have also suggested tumour promoting activities for these laxatives. Although the short-term use of these substances is generally safe, long-term use cannot be recommended.

Colonic motility in health and disease

Being the final pathway for chyme and digestive residues, the colorectum influences bowel function critically. The most important and relevant symptoms of colonic dysfunction are diarrhea, constipation, urgency, and pain. Despite the effects of many investigators, over several decades, the motor physiology of the human colon is still relatively obscure. Most is known about patterns of colonic transit. In practice, measurements of transit are the best characterized and most widely available tests of colonic motor function. Colonic hypersensitivity, implying an abnormality of afferent signaling, is assuming greater importance in the pathophysiology of conditions as common as IBS and inflammatory bowel disease.

Effects of long-term laxative treatment on neuropeptides in rat mesenteric vessels and caecum

In order to investigate the toxic effects of long-term treatment with anthraquinone laxatives, rats were fed either chocolate alone, or chocolate adulterated with senna or danthron (1,8-dihydroxyanthraquinone) for 5 months. Mesenteric blood vessels and the outer muscle layers of the caecum, together with the myenteric plexus, were examined using ultrastructural, histochemical, immunohistochemical and immunoassay techniques. There was no ultrastructural evidence of degeneration in either the mesenteric vessels or the caecum. In the mesenteric vessels, levels of neuropeptide Y were significantly reduced in the danthron-fed rats, but levels of substance P (SP), calcitonin gene-related peptide (CGRP) and vasoactive intestinal polypeptide (VIP) were unaffected by all treatments. In the caecum, VIP-, SP- and CGRP-immunoreactivity and catecholamine-fluorescence were unchanged by the laxative treatments.

Resistance of myenteric neurons in the rat's colon to depletion by 1,8-dihydroxyanthraquinone

Earlier reports have suggested that anthraquinone purgatives in excessive amounts cause degeneration of neurons in the enteric nervous system. Danthron (1,8-dihydroxyanthraquinone) was administered to rats in their drinking water for four months. The effects of the drug on the total number of neurons and on the immunoreactivity of eight putative neurotransmitters in the myenteric plexus of the colon have been assessed. No differences were found between the treated animals and their controls, indicating that the drug does not kill myenteric neurons. These results agree with recent observations on the effects of senna in rats and mice, and do not support earlier claims that myenteric neurons are killed by anthraquinone purgatives.