Anal Motility Research Articles

Clinical effects of biofeedback therapy on functional constipation caused by pelvic floor dys-synergia

Objective To explore the clinical effects of biofeedback (BF) therapy on functional constipation (FC) caused by pelvic floor dys-synergia (PFD). Methods Forty patients with FC caused by PFD were enrolled and given BF therapy twice a week for 5 weeks. Constipation symptom scores and anal motility were recorded before and after the therapy. Results All the patients enrolled finished the BF therapy, with a total effectiveness rate of 80%. Both the constipation symptom scores and anal residual pressure during defecation had decreased significantly after therapy. Rectal gradient pressure, however, had increased significantly. Conclusion Biofeedback can relieve the clinical symptoms of FC and improve pelvic floor coordination during defecation. It is worth applying in clinical practice. Key words: Biofeedback; Pelvic floor dys-synergia; Constipation; Constipation symptom scores; Anal motility

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.

The identification of specialized pacemaking cells in the anal sphincters

Interstitial cells of Cajal (ICC) are claimed to generate the electrical activity in the colon and stomach. As the external (EAS) and internal (IAS) anal sphincters exhibit resting electrical activity, we hypothesized the presence of ICC in these sphincters. This hypothesis was investigated in the current study. Specimens from the EAS and IAS were taken from normal areas of the anorectum which had been surgically excised by abdominoperineal operation for rectal cancer of 28 patients (16 men, 12 women, mean age 42.2+/-4.8 years). The specimens were subjected to c-kit immunohistochemistry. Controls for the specificity of the antisera consisted of tissue incubation with normal rabbit serum substituted for the primary antiserum. Fusiform, c-kit positive, ICC-like cells were detected in the anal sphincters; they had dendritic processes. They were clearly distinguishable from the non-branching, c-kit negative smooth and striated muscle cells of the anal sphincters. The specimens contained also c-kit positive mast cells, but they had a rounded body with no dendritic processes. Immunoreactivity was absent in negative controls in which the primary antibody was omitted. We have identified, for the first time, cells in EAS and IAS with morphological and immunological phenotypes similar to ICCs of the gut. These cells appear to be responsible for initiating the slow waves recorded from the anal sphincters and for controlling their activity. A deficiency or absence of these cells may affect the anal motile activity. Studies are needed to explore the role of these cells in anal motility disorders.

Effects of loperamide on ileoanal pouch function.

Opioid analogues are used to manage increased bowel frequency in patients with an ileoanal reservoir. The aim of the study was to determine the clinical efficacy of loperamide in patients with an ileoanal reservoir and to assess its effect on pouch motility. Fourteen patients with a pouch who had normal pouch emptying and anal function were studied. Ambulatory pouch and anal motility, and stool weights, were recorded for 24 h while taking no medication and for 24 h while receiving 8 mg loperamide. In a second analysis, patients were divided on the basis of bowel frequency into those with 4 or fewer motions (good function; n=6) and those with more than 6 per day (poor function; n=8), to determine any differential effects of loperamide. Loperamide decreased median bowel frequency (no loperamide 5.5 versus loperamide 4.0, P=0.03) and 24-h stool weight (610 g versus 413 g, P=0.03) but not individual stool weights. Patients with poor function had both higher bowel frequency (8.0 versus 3.5 per 24 h, P=0.004) and higher stool weight (728 g versus 430 g, P=0.05) with no treatment than those with good function. High-amplitude pouch pressure waves were greater in number before defaecation in patients with poor function and did not decrease with loperamide, in contrast to patients with good function. Pouch baseline pressure decreased after defaecation to a similar extent in both groups and was not affected by loperamide. Loperamide 8 mg per day reduces bowel frequency by reducing total stool weight, not individual stool weights. In patients with good function it also affects pouch motility. High bowel frequency is associated with increased pouch high-pressure waves.

Effects of short term sacral nerve stimulation on anal and rectal function in patients with anal incontinence

BACKGROUNDSome patients with faecal incontinence are not amenable to simple surgical sphincter repair, due to sphincter weakness in the absence of a structural defect.AIMSTo evaluate the efficacy and possible mode...

The effect of pelvic nerve stimulation on recto-anal motility in the cat

Rectal and anal motility responses to pharmacological manipulation of neuro-transmission and graded efferent electrical pelvic nerve stimulation were investigated in alpha-1-chloralose anaesthetized cats. N ω -nitro- l-arginine ( l-NNA), a competitive inhibitor of nitric oxide synthase, did not influence spontaneous rectal and anal motility. No significant change in anal pressure or rectal tone was observed after sectioning the pelvic nerves in animals pretreated with l-NNA. The effect of pelvic nerve stimulation on anal tone was varying and depended upon the intensity of stimulation and the prevailing anal tone. A reduction of anal tone on pelvic nerve stimulation was consistently converted to an increase of anal tone after pretreatment with l-NNA. The rectal response to pelvic nerve stimulation was unchanged by l-NNA. Residual increase of anal tone observed on pelvic nerve stimulation after l-NNA and noradrenergic blockade was partly sensitive to hexamethonium and abolished by atropine. The results suggest that there is no tonic influence on rectal and anal motility via nitric oxide mechanisms. On the other hand, the reduction of anal tone on high intensity pelvic nerve stimulation seemed to be dependent on the release of nitric oxide. An excitatory cholinergic component of the smooth muscle contractility of the feline anal canal, partly sensitive to hexamethonium, was demonstrated to be conveyed in the pelvic nerves.

Reflex interaction from the urinary bladder and the rectum on anal motility in the cat

The intrinsic recto-anal inhibitory reflex (RAIR) and the extrinsic vesico-anal excitatory reflex were studied in anaesthetized cats in order to explore the nervous components of anal pressure regulation. The magnitude of the RAIR was documented at varying levels of anal pressure. Minimal anal pressure during RAIR was positively correlated to anal pressure immediately prior to rectal distension. It was possible to elicit the vesico-anal excitatory reflex concomitantly with an ongoing RAIR. It was also possible to elicit a RAIR during the vesico-anal excitatory reflex. The magnitude of the pressor reflex response was not changed by concomitant activation of the inhibitory reflex and vice versa. This suggests an independent action on the internal anal sphincter (IAS) of the two reflexes. Spontaneous detrusor contractions were abolished by rectal distension. However, an escape phenomenon from this inhibition was observed, suggesting a spinal, associative, connection. The results support the concept of a direct action of both extrinsic and intrinsic nervous mechanisms on the smooth muscle of the IAS.

Ambulatory pouch and anal motility in patients with ileo-anal reservoirs.

Twelve patients were studied for a median of 18 hours (range 8.5-21.5 hr) by continuous, ambulatory, simultaneous pouch and anal manometry 10-85 months after restorative proctocolectomy. Two main patterns of motility were observed: (1) Large isolated contractions up to 68 cm H2O in amplitude and up to 67 seconds in duration were present in ten patients. These were often associated with the urge to defaecate and were more frequent before defaecation than after but did not appear to be associated with expulsion of faeces from the pouch. In two patients atypical large isolated contractions up to 378 cm H2O in amplitude were observed. (2) Rhythmic contractions at a frequency of 7-11 per minute and amplitude of 24-330 cm H2O, occurred for a duration of 18 seconds to 18 minutes in six patients. In the other six patients this motility pattern was not seen. Of the 12 patients nine were considered to have good function (five or less bowel actions per 24 hours) and three poor function (ten or more bowel actions per 24 hours). Rhythmic activity was the predominant motility pattern in all three with poor function whereas large isolated contractions predominated in those with good function, although there was considerable overlap in the types of motility observed between patients with good and poor function. Mean pouch pressure tended to be higher in patients with poor function than in those with good function both throughout the entire recording and during sleep. In a number of patients simultaneous anal recordings revealed the presence of slow waves and falls in pressure, some of which were associated with a simultaneous rise in pouch pressure.

Human anal motility while fasting, after feeding, and during sleep

The aim of this study was to determine whether the human anal sphincter responds dynamically to changing physiological states. In 19 healthy human subjects, intraluminal anal canal pressure was measured with a 5-cm perfused sleeve sensor during the day while fasting (3 hours) and after feeding (3 hours) and at night during sleep (8 hours). Daytime mean anal canal pressures (± SEM) while fasting (50 ± 3 mm Hg) were similar to those after feeding (49 ± 3 mm Hg) and to those at night during sleep (49 ± 3 mm Hg). Marked minute-to-minute variations in mean pressure occurred in all three periods, however, as did large phasic increases and decreases in pressure (> 20 mm Hg) and small phasic changes in pressure < 20 mm Hg (anal slow waves). The minute-to-minute variations in mean pressure were greater during the awake fed state (4 ± 1 mm Hg/min) than at night during sleep (2 ± 1 mm Hg/ min; P < 0.03), as were the number of large phasic waves per minute (increases in pressure: awake, fed = 0.5 ± 1 waves/min, night = 0.3 ± 0.1 waves/ min, P < 0.05; decreases in pressure: awake, fed = 0.4 ± 0.1 waves/min, night = 0.2 ± 0.1 waves/ min, P < 0.05). Anal small waves had a similar frequency of about 17 waves/min in all three states. In conclusion, the anal sphincter maintains a continuous pressure barrier to rectal outflow both during the day and at night during sleep. However, marked minute-to-minute variations in mean pressure and large phasic increases and decreases in pressure do occur. Both are fewer at night during sleep.