Relaxation Of Internal Anal Sphincter Research Articles

Parasympathetic control of gastrointestinal motility and cross-branch actions of parasympathetic neuromodulation.

Parasympathetic control of gastrointestinal motility and cross-branch actions of parasympathetic neuromodulation.

The role of dilatation methods and lateral subcutaneous sphincterotomy in the internal anal sphincter spasm treatment (systematic literature review and meta-analysis)

The main link in the pathogenesis of anal fissure is a spasm of the internal sphincter of the rectum, in connection with which many methods of muscle relaxation have been developed. A special place is occupied by dilatation methods, which are quite diverse. To assess their effectiveness and safety, the authors carried out a systematic review and meta-analysis of 9 selected randomized clinical trials comparing the results of treatment of chronic anal fissure using dilatation methods of internal anal sphincter relaxation and the traditionally used method of lateral subcutaneous sphincterotomy. The results of treatment of 716 patients were analyzed with an assessment of such indicators as the frequency of fissures epithelialization, postoperative complications, and the development of anal sphincter insufficiency and relapses of the disease. There were no statistically significant differences in the frequency of fissure healing in the groups with the use of dilatation methods of internal sphincter relaxation and lateral subcutaneous sphincterotomy (OR=1; CI=0.34;2.96; p=1). When assessing the risk of the disease recurrence in both groups, there were also no statistically significant differences (OR=0.93; CI=0.56;1.56; p=0.79). Postoperative complications were also comparable in both groups (OR=0.81; CI=0.4;1.63; p=0.55). There were no statistically significant differences in the incidence of anal incontinence (OR=1; CI=0.34;2.96; p=1). It should be noted that the use of uncontrolled dilatation is associated with a high risk of developing anal incontinence, while the introduction of controlled dilatation reduces the risk of this complication to a minimum. The use of controlled dilatation methods for relaxation of the internal sphincter is a safe alternative to lateral subcutaneous sphincterotomy, including in the treatment of anal fissures in combination with hemorrhoids.

A systematic review of translation and experimental studies on internal anal sphincter for fecal incontinence.

The complexity in the molecular mechanism of the internal anal sphincter (IAS) limits preclinical or clinical outcomes of fecal incontinence (FI) treatment. So far, there are no systematic reviews of IAS translation and experimental studies that have been reported. This systematic review aims to provide a comprehensive understanding of IAS critical role in FI. Previous studies revealed the key pathway for basal tone and relaxation of IAS in different properties as follows; calcium, Rho-associated, coiled-coil containing serine/threonine kinase, aging-associated IAS dysfunction, oxidative stress, renin-angiotensin-aldosterone, cyclooxygenase, and inhibitory neurotransmitters. Previous studies have reported improved functional outcomes of cellular treatment for regeneration of dysfunctional IAS, using various stem cells, but did not demonstrate the interrelationship between those results and basal tone or relaxation-related molecular pathway of IAS. Furthermore, these results have lower specificity for IAS-incontinence due to the included external anal sphincter or nerve injury regardless of the cell type. An acellular approach using bioengineered IAS showed a physiologic response of basal tone and relaxation response similar to human IAS. However, in both cellular and acellular approaches, the lack of human IAS data still hampers clinical application. Therefore, the IAS regeneration presents more challenges and warrants more advances.

Treatment of chronic anal fissure botulinum toxin type A 40 U in comparison with lateral subcutaneous sphincterotomy (NCT03855046)

AIM: to improve the results of chronic anal fissure treatment.PATIENTS AND METHODS: the prospective randomized study included 176 patients divided in two groups. Eighty-eight patients underwent fissure excision in combination with injection of botulinum toxin type A (incobotulinum toxin) into the internal anal sphincter (main group, BTA), and 88 patients underwent anal fissure excision in combination with lateral subcutaneous sphincterotomy (control group, LIS).RESULTS: on the 30th day after surgery, spasm of internal anal sphincter, according to profilometry, persisted in 14.8% of patients of the main group (BTA) and 22.7% of patients in the control group (LSS) (p = 0.18), and on the 60th day in 20.4% and 14.8% of patients, respectively (p = 0.32). On the 60th day after surgery, the postoperative wound did not epithelialize in 14% of patients in the BTA group and 1% of the LSS group (p = 0.0006). On the 30th day after surgery, complaints of incontinence were noted by 32% of patients in the BTA group and 31% in the LSS group (p = 0.87), on the 60th day — 7% and 11% of patients, respectively (p = 0.29). The intensity of pain after surgery in the compared groups did not differ both after defecation and during the day (p > 0.05). Expansion of the surgery volume increases the chance of developing temporary anal sphincter incontinence (ASI) by 2.44 times on the 30th day of observation (p = 0.01) and by 3 times — on day 60 (p = 0.04). The use of BTA as a method of internal anal sphincter relaxation increases the chance of slowing down the epithelization of the postoperative wound by 13.7 times [p = 0.01], and the expansion of the surgery volume — by 3.47 times [p = 0.03].CONCLUSION: the use 40 U of botulinum toxin type A after anal fissure excision is not inferior to lateral subcutaneous sphincterotomy in elimination of spasm internal anal sphincter with a comparable incidence of temporary anal sphincter incontinence within 2 months after surgery. Neurotoxin serves as an alternative to sphincterotomy, however, in some cases, it requires the addition of a agent containing human recombinant epidermal growth factor to the postoperative management of patients.

Can Propofol Be Used to Assess the Presence of the Rectoanal Inhibitory Reflex During Anorectal Manometry Studies?

To study changes in intra-anal pressure (IAP) and characteristics of the rectoanal inhibitory reflex (RAIR) during anorectal manometry (ARM) in patients undergoing anesthesia induction with propofol. Prospective study in which ARM was performed at baseline while patients were awake and repeated after propofol-induced anesthesia. We studied IAP and the presence and characteristics of the RAIR before and after propofol. A total of 27 patients were included (63% male; 9.2 years). Three patients had obstructive symptoms after Hirschsprung disease repair (HSCR), and 24 had intractable constipation. At baseline, the RAIR was present on 21 of 27 patients and absent on 6 of 27. Of the six patients with an absent RAIR, it remained absent in four of six (three known HSCR, and one new diagnosis of IAS achalasia), and two of six had a normal RAIR during propofol. Therefore, RAIR was present in all patients with constipation. The mean resting IAP was significantly lower after propofol. The percentage of IAS relaxation after lower balloon volume inflations was significantly higher during propofol (P < 0.05). No difference was observed over the latency time or the total relaxation time after propofol. Propofol can be used to assess the presence of the RAIR during ARM in children who are uncooperative and undergoing other procedures under anesthesia. On the other hand, propofol significantly reduces the resting IAP and increases the percentage of internal anal sphincter relaxation after balloon distention. These findings may impact the interpretation to decide if an intervention is needed, or if there is a possible spinal neuropathy.

Oscillating calcium signals in smooth muscle cells underlie the persistent basal tone of internal anal sphincter.

A persistent basal tone in the internal anal sphincter (IAS) is essential for keeping the anal canal closed and fecal continence; its inhibition via the rectoanal inhibitory reflex (RAIR) is required for successful defecation. However, cellular signals underlying the IAS basal tone remain enigmatic. Here we report the origin and molecular mechanisms of calcium signals that control the IAS basal tone, using a combination approach including a novel IAS slice preparation that retains cell arrangement and architecture as in vivo, 2-photon imaging, and cell-specific gene-modified mice. We found that IAS smooth muscle cells generate two forms of contractions (i.e., phasic and sustained contraction) and Ca2+ signals (i.e., synchronized Ca2+ oscillations [SCaOs] and asynchronized Ca2+ oscillations [ACaOs]) that last for hours. RyRs, TMEM16A, L-type Ca2+ channels, and gap junctions are required for SCaOs, which account for phasic contraction and 75% of sustained contraction. Nevertheless, only RyRs are required for ACaOs, which contribute 25% of sustained contraction. Nitric oxide, the primary neurotransmitter mediating the RAIR, blocks both types of Ca2+ signals, leading to IAS's full relaxation. Our results show that the oscillating nature of Ca2+ signals generates and maintains the basal tone without causing cytotoxicity to IAS. Our study provides insight into fecal continence and normal defecation.

Spontaneous Internal Anal Sphincter Relaxation During High-resolution Anorectal Manometry Is Associated With Peripheral Neuropathy and Higher Charlson Comorbidity Scores in Patients With Defecatory Disorders.

Background/AimsWe aimed to evaluate associations between comorbidities, peripheral neuropathy, and spontaneous internal anal sphincter relaxation (SAR) in patients with defecatory disorders.MethodsA patient was considered to exhibit SAR during high-resolution anorectal manometry (HR-ARM) when the nadir pressure is < 15 mmHg and the time from onset to relaxation was ≥ 15 seconds in the resting pressure frame. A case-control study was performed using HR-ARM data collected from 880 patients from January 2010 to May 2015. We identified 23 cases with SAR (median age 75 years; 15 females; 12 fecal incontinence and 11 constipation). We compared HR-ARM values, Charlson index comorbidity scores, neuropathy, and the prevalence of diseases that potentially cause neuropathy between controls and SAR patients. Each SAR case was compared to 3 controls. Controls were selected to match the age, gender, and examination year of each SAR case.ResultsCompared to controls (26.1%), SAR patients (52.2%) exhibited a significantly higher frequency of fecal incontinence. SAR patients also had higher Charlson index scores (5 vs 4, P = 0.028). Nine of 23 SAR patients (39.1%) exhibited peripheral neuropathy— this frequency was higher than that for the control group (11.6%; P = 0.003). Diseases that potentially cause neuropathy were observed in 17 of 23 SAR cases and 32 of 69 controls (P = 0.022).ConclusionsSAR develops in patients with constipation and fecal incontinence but is more common in patients with fecal incontinence. Our controlled observational study implies that SAR is associated with peripheral neuropathy and more severe comorbidities.

Botulinum toxin injections after surgery for Hirschsprung disease: Systematic review and meta-analysis

BACKGROUNDA large proportion of patients with Hirschsprung disease experience persistent obstructive symptoms after corrective surgery. Persistent obstructive symptoms may result in faecal stasis that can develop into Hirschsprung-associated enterocolitis, a potential life-threatening condition. Important treatment to improve faecal passage is internal anal sphincter relaxation using botulinum toxin injections.AIMTo give an overview of all empirical evidence on the effectiveness of botulinum toxin injections in patients with Hirschsprung disease.METHODSA systematic review and meta-analysis was done by searching PubMed, EMBASE and the Cochrane Library, using entry terms related to: (1) Hirschsprung disease; and (2) Botulinum toxin injections. 14 studies representing 278 patients met eligibility criteria. Data that were extracted were proportion of patients with improvement of obstructive symptoms or less enterocolitis after injection, proportion of patients with adverse effects and data on type botulinum toxin, mean dose, average age at first injection and patients with associated syndromes. Random-effects meta-analysis was used to aggregate effects and random-effects meta-regression was used to test for possible confounding factors.RESULTSBotulinum toxin injections are effective in treating obstructive symptoms in on average 66% of patients [event rate (ER) = 0.66, P = 0.004, I2 = 49.5, n = 278 patients]. Type of botulinum toxin, average dose, average age at first injections and proportion of patients with associated syndromes were not predictive for this effect. Mean 7 duration of improvement after one botulinum toxin injections was 6.4 mo and patients needed on average 2.6 procedures. There was a significant higher response rate within one month after botulinum toxin injections compared to more than one month after Botulinum toxin injections (ER = 0.79, vs ER = 0.46, Q = 19.37, P < 0.001). Botulinum toxin injections were not effective in treating enterocolitis (ER 0.58, P = 0.65, I2 = 71.0, n = 52 patients). There were adverse effects in on average 17% of patients (ER = 0.17, P < 0.001, I2 = 52.1, n = 187 patients), varying from temporary incontinence to mild anal pain.CONCLUSIONFindings from this systematic review and meta-analysis indicate that botulinum toxin injections are effective in treating obstructive symptoms and that adverse effects were present, but mild and temporary.

Sa1665 – Spontaneous Internal Anal Sphincter Relaxation on Highresolution Anorectal Manometry is Related to the Presence of Peripheral Neuropathy and Higher Charlson Comorbidity Scores in Patients with Defecatory Disorders

Sa1665 – Spontaneous Internal Anal Sphincter Relaxation on Highresolution Anorectal Manometry is Related to the Presence of Peripheral Neuropathy and Higher Charlson Comorbidity Scores in Patients with Defecatory Disorders

Preservation of the colo-anal reflex in colonic transection and post-operative Hirschsprung's disease: Potential extrinsic neural pathway.

The colo-anal reflex is a distinct reflex whereby the internal anal sphincter (IAS) relaxes in association with colonic high amplitude propagating contractions (HAPCs) in contrast to the recto-anal inhibitory reflex (RAIR), which is characterized by IAS relaxation upon rectal distension. The RAIR is mediated by the myenteric plexus and therefore absent in Hirschsprung disease. We retrospectively assessed the presence and the characteristics of the colo-anal reflex in children in whom large bowel continuity had been surgically disrupted to assess the role of the extrinsic nervous system in the reflex. High-resolution (HR) colonic manometry and HR-anorectal manometry were used to evaluate both colonic and anal motor activity in ten children with treatment-unresponsive slow transit constipation (STC), who had previously undergone left-sided colostomy formation with consequent disruption of the bowel continuity, and in two children with Hirschsprung's disease (HSCR), who had previously undergone distal colon resection followed by Duhamel pull-through. Eight children with STC, normal colonic motor activity, and preserved large bowel continuity served as a control group. The presence and characteristics of colo-anal reflex were analyzed. In the study group, all patients showed the presence of both normal HAPCs and the presence of the colo-anal reflex. In two cases of HSCR, RAIR was absent; however, both patients demonstrated a colo-anal reflex. In children with disrupted continuity of the colon and/or abnormal anal reflex, the colo-anal reflex is still preserved suggesting that it is mediated by a different pathway from the RAIR, possibly an extrinsic neural pathway.

Diagnostic Role of Anal Sphincter Relaxation Integral in High-Resolution Anorectal Manometry for Hirschsprung Disease in Infants

To investigate the possible diagnostic role of anal sphincter relaxation integral (ASRI) in high-resolution anorectal manometry (HRAM) for Hirschsprung disease. We performed conventional anorectal manometry (ARM) in 24 infants (8 with Hirschsprung disease and 16 without Hirschsprung disease) and HRAM in another 21 infants (9 with Hirschsprung disease and 12 without Hirschsprung disease) before and after October 2014. All infants underwent rectal suction biopsy for confirmation of Hirschsprung disease. We quantified rectoanal inhibitory reflex (RAIR) adequacy by calculating the ASRI in HRAM study at pressure cutoffs of less than 10, 15, and 20 mm Hg (ASRI10, ASRI15, and ASRI20, respectively) and investigated the diagnostic utility. Patients with Hirschsprung disease who underwent HRAM had significantly lower ASRI10, ASRI15, and ASRI20 values than did infants without Hirschsprung disease (P = .0002, .0002, and .0003, respectively), indicating significant difference in internal anal sphincter relaxation during RAIR test between these 2 groups. ASRI10 exhibited a greater diagnostic accuracy, area under the curve, sensitivity, and specificity than did ASRI15 and ASRI20 for Hirschsprung disease. Moreover, the diagnostic accuracy of HRAM for Hirschsprung disease based on ASRI10 <7 mm Hg.s.cm was significantly greater than that of conventional ARM (P = .02). ASRI10 may be indicative of the adequacy of RAIR by HRAM in infants, thus assisting the diagnosis of Hirschsprung disease. The diagnostic accuracy of HRAM (based on the ASRI10 value) is greater than that of conventional ARM for Hirschsprung disease. ASRI10 may be used in an automatic HRAM analysis system for the diagnosis of anorectal motility disorders.

The “simultaneous contractions” of the human colon are a fast propagating rhythmic neurogenic motor pattern associated internal anal sphincter relaxation and gas expulsion, not an artifact of abdominal pressure changes

The “simultaneous contractions” of the human colon are a fast propagating rhythmic neurogenic motor pattern associated internal anal sphincter relaxation and gas expulsion, not an artifact of abdominal pressure changes

Hirsch-Sprung’s Disease – A Panchkarma Approach for the Congenital Malformation of Colon

Hirschsprung’s disease is a congenital disorder of large intestine in which certain ganglionic cells are absent in a particular segment of colon resulting in absence of peristalsis. The lack of movement of intestine and the failure of relaxation of internal anal sphincter produces varying degree of intestinal obstruction, which results in symptoms like- constipation, abdominal distension, nausea and loss of appetite etc. In allopathic medical science the treatment is surgical removal of the affected area followed by anastomosis. In present case study an Ayurvedic approach was considered by analyzing the factors involved at the level of dosha-dushya and srotas for the disease. And the line of treatment was planned as deepan-pachan, snehan, swedan, mridu samshodhan with basti, mridu virechaka aushadhies, vata-anuloman and pathya ahara-vihara. By following this, encouraging results were obtained in this case with regular bowel pattern and relief in other symptoms

Proteinase-activated receptor-1 (PAR1) and PAR2 mediate relaxation of guinea pig internal anal sphincter

Activation of proteinase-activated receptor-1 (PAR1) and PAR2 stimulates contraction of the rat but relaxation of the guinea pig colon. The aim of the present study was to investigate PAR effects on internal anal sphincter (IAS) motility. We measured relaxation of isolated muscle strips from the guinea pig IAS caused by PAR agonists using isometric transducers. Reverse transcription polymerase chain reaction (RT-PCR) was performed to determine the existence of PAR. In the IAS, thrombin and PAR1 peptide agonists TFLLR-NH2 and SFLLRN-NH2 evoked moderate to marked relaxation in a concentration-dependent manner. In addition, trypsin and PAR2 peptide agonists 2-furoyl-LIGRLO-NH2, SLIGRL-NH2 and SLIGKV-NH2 produced relaxation. In contrast, both PAR1 and PAR2 inactive control peptides did not elicit relaxation. Furthermore, the selective PAR1 antagonist vorapaxar and PAR2 antagonist GB 83 specifically inhibited thrombin and trypsin-induced relaxations, respectively. RT-PCR revealed the presence of PAR1 and PAR2 in the IAS. This indicates that PAR1 and PAR2 mediate the IAS relaxation. The relaxant responses of TFLLR-NH2 and trypsin were attenuated by N(omega)-Nitro-L-arginine (L-NNA), indicating involvement of NO. These responses were not affected by tetrodotoxin, implying that the PAR effects are not neurally mediated. On the other hand, PAR4 agonists GYPGKF-NH2, GYPGQV-NH2 and AYPGKF-NH2 did not cause relaxation or contraction, suggesting that PAR4 is not involved in the sphincter motility. Taken together, these results demonstrate that both PAR1 and PAR2 mediate relaxation of the guinea pig IAS through the NO pathway. PAR1 and PAR2 may regulate IAS tone and might be potential therapeutic targets for anal motility disorders.

Internal anal sphincter relaxation associated with bisacodyl‐induced colonic high amplitude propagating contractions in children with constipation: a colo‐anal reflex?

Describe the association of internal anal sphincter (IAS) relaxation with colonic high- amplitude peristaltic contractions (HAPCs). Retrospective review of colon manometry tracings of children with constipation to determine the IAS relaxation characteristics associated with HAPC's (HAPC-IASR) events and compare them to the those seen during the performance of the anorectal manometry (ARMRAIR) events. A total of 70 HAPC- IASRs were observed in 15 patients, 65 after bisacodyl, two during fasting and three after a meal. In 64% of events, the IAS relaxation started when the HAPC reached left colon and in 36% as proximal as the hepatic flexure. High- amplitude peristaltic contraction propagation seems to be important in HAPC-IASR characteristics; those propagating distal to sigmoid colon demonstrated larger and longer IAS relaxation as well as lower residual pressure, but equivalent resting pressure compared with HAPC's ending proximal to sigmoid colon. Although IAS resting pressure was comparable for ARM-RAIRs and HAPC-IASRs, the duration and magnitude of anal relaxation was higher, and the anal residual pressure was lower in HAPC-IASRs. We demonstrated that IAS relaxation in constipated children is associated with HAPCs migrating in the proximal and distal colon; in most cases, starting when peristalsis is migrating through left colon and in an important proportion while migrating proximally. We also demonstrated that HAPC-IASRs are different from ARM-RAIRs suggesting a neurally mediated reflex. Finally, the IAS relaxation characteristics are highly dependent on the degree of propagation of HAPCs, which could have important implications in the understanding of defecation disorders.

Region-related modular nerve-dependent motor activity in anorectum--cholinergic and nitrergic contribution to rat model.

Disturbances of enteric nerve-mediated anorectal evacuation mechanisms have medical and social impact. The study aimed at further eliciting the contribution of cholinergic and nitrergic neurotransmission systems to modular nerve networks in different regions of Wistar rat anorectum. Electrical field stimulation (EFS, 0.8 ms, 40 V, 2, 5 or 10 Hz, 20 s), computerized mechanographic on-line setup and drugs were used to evaluate the motor responses of isolated rings from circular muscle of rectum (proximal, middle, and distal part), internal anal sphincter, and anal canal. Twitch-like frequency-dependent contractions, more pronounced in rectal preparations, characterized the modular motor responses of rectal circular muscle rings and anal canal. Depending on the frequency of stimulation, the motor activity of internal anal sphincter varied from deep long-lasting relaxation to initial short-lasting relaxation, followed by a contraction. Electrically-evoked responses of anorectal preparations were tetrodotoxin (0.1 microM)-sensitive. In the presence of atropine (0.3 microM) the contractions of rectal rings decreased, relaxation of internal anal sphincter increased and inhibition of the contractions of the anal canal occurred, followed by relaxation. During atropine treatment, NG-nitro-L-arginine (0.5 microM) increased the contractile responses and suppressed internal anal sphincter relaxations. L-arginine (0.5 microM) decreased the contractions and extended the relaxations of internal anal sphincter and anal canal. Our results suggest that cholinergic and nitrergic systems are not equally involved in modular nerve networks of various regions of anorectum. Cholinergic transmission is more expressed in distal rectum, underlying its contractile potency, while nitric oxide-dependent transmission(s) control the relaxation ability of the internal anal sphincter and anal canal.

Altered temporal characteristics of the rectoanal inhibitory reflex in patients with abdominal distension

The rectoanal inhibitory reflex (RAIR) is important in gas and stool evacuation. We examined RAIR features in patients with chronic constipation who exhibited bloating with and without abdominal distension, to determine whether alterations in RAIR may be a factor in the pathogenesis of abdominal distension. Seventy-five female patients with chronic constipation with or without abdominal distension were included in the study. The presence or absence of abdominal distension was assessed according to the Rome II questionnaire. All patients underwent both RAIR and rectal sensitivity testing, and specific RAIR parameters were analyzed. Patients were divided into two groups: abdominal bloating with distension (D, n = 55) and abdominal bloating without distension (ND, n = 20). D had a longer time to the onset of anal sphincter inhibition (latency of inhibition) (P = 0.03) compared with ND. In logistic regression analysis, a combination of age, latency of inhibition and the time measured from onset of inhibition to the point of maximum inhibition predicted abdominal distension (P = 0.002). There were no differences between groups for the time from point of maximum inhibition to recovery and for the percentage of internal anal sphincter relaxation. This is the first study to examine the role of RAIR in patients with abdominal distension. Female patients with constipation and abdominal distension exhibited differences in the temporal characteristics of, but not in the degree of, anal sphincter relaxation compared with patients without distension. Since this study was uncontrolled, further studies are necessary to determine the contribution of altered anorectal reflexes to abdominal distension.

Prevalence and Pathophysiology of Functional Constipation Among Women in Catalonia, Spain

Specific treatment of functional bowel disorders requires precise diagnosis. However, prevalence and subtypes of functional constipation among women are not completely understood. Our aim was to assess the prevalence of functional constipation and investigate the subtypes of dyssynergic defecation and slow transit constipation among Spanish women. We performed a prospective epidemiological study in healthy young women and retrospective pathophysiological studies in 2 patient cohorts of women with functional constipation according to Rome II criteria. Referral centers at Clínica Sagrada Familia, Barcelona, Spain, and Hospital de Mataró, Mataró, Spain. The epidemiological study included 600 healthy young women, aged 37.1 (SD, 8.2) years. Patient cohort 1 comprised 172 women with functional constipation without symptoms of pelvic floor dysfunction, ranging in age from 18 to 45 years. Patient cohort 2 comprised 106 women with functional constipation and symptoms of dyssynergic defecation, ranging in age from 45 to 65 years. In healthy women, a questionnaire was used to determine rates of functional constipation, dyssynergic defecation, and slow transit constipation. In patients, results of anorectal manometry, EMG, and colonic transit studies were reviewed to assess subtypes of functional constipation; in addition, results of dynamic videoproctography were reviewed in cohort 2 to assess the role of structural pelvic floor disorders. The prevalence of functional constipation in healthy young women was 28.8%; symptoms of dyssynergic defecation were found in 8.2%, those of isolated slow transit in only 0.17%. In patient cohort 1, a total of 143 patients (83.1%) showed dyssynergic defecation: 117 patients (68.0%) had paradoxical external anal sphincter contraction and 26 (15.1%) had impaired internal anal sphincter relaxation). Slow transit constipation without dyssynergia was observed in 15 (8.7%). Up to 40.2% of patients with dyssynergia also had delayed colonic transit. In the cohort of 106 women with dyssynergic defecation, videoproctography showed impaired puborectal relaxation in 64 patients (60.4%), anterior rectocele in 65 (61.3%), and rectal prolapse in 13 (12.3%). We could not estimate the prevalence and subtypes of irritable bowel syndrome in the epidemiological study. Functional constipation is extremely prevalent among young, healthy, Spanish women, dyssynergic defecation being the most prevalent subtype. Slow transit constipation without dyssynergic defecation is uncommon. Structural pelvic floor disorders are highly prevalent in middle-aged women with dyssynergic defecation.

Modular and functionally-different descending recto-anal motor pathways in a rat model

Abstract We evaluated the motor responses in recto-anal preparations obtained from rats, in terms of the excitation displayed by modules of nerve networks and descending distally directed pathways, when subjected to the mechanographic on-line technique, a partitioned organ bath, electrical stimulation (EFS, 0.8 ms, 5 Hz) and distension. EFS elicited modular contractions, which increased in amplitude distally, in circular muscle rings isolated from the proximal, middle or distal rectum. The modular responses of the internal anal sphincter or anal canal were relaxation or contraction, respectively. The application of EFS to the distal rectum induced a descending contractile response in the anal canal (5.24±0.34 mN), while distension by balloon evoked a descending response consisting of contraction (1.72±0.20 mN) followed by relaxation (3.42±0.24 mN). The responses were sensitive to tetrodotoxin. Atropine considerably depressed the contractions in all preparations. Whether or not atropine was present, L-NNA increased the excitatory responses, while L-arginine decreased the contractions and extended the relaxation of internal anal sphincter and anal canal. The results suggest that excitatory neurotransmission(s) expressed in the distal rectum dominate modular nerve networks. Functionally-different descending pathways are involved in the motor activity of the anal canal. Stimulatory cholinergic pathways are dependent on the electrically-induced excitation, and inhibitory nitrergic pathways are sensitive to distension of rectal wall.

Proteinase-Activated Receptor-1 (PAR1) and PAR2 but Not PAR4 Mediate Relaxation of Guinea-Pig Internal Anal Sphincter

Proteinase-Activated Receptor-1 (PAR1) and PAR2 but Not PAR4 Mediate Relaxation of Guinea-Pig Internal Anal Sphincter