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Biomedical subjects

A Shafik

Publications and source records attributed to A Shafik.

At least 37 records · Page 2Linked to original sources
PubMed2001

Electric activity of the rectosigmoid canal and its relation to rectal and sigmoid electric activity: an evidence of a sphincteric function of the rectosigmoid canal.

We have previously demonstrated that the rectosigmoid junction is more than a junction: it is a segment with a mean length of 2.8 cm which we termed the 'rectosigmoid canal' (RSC). Our data support the existence of a physiologic and anatomic sphincter at the RSC which regulates the passage of stools from the sigmoid colon (SC) to the rectum (R). In view of its sphincteric action we investigated the hypothesis that the RSC has a higher electric activity than that of the SC and R. The tests were performed during repair of huge incisional hernia in 11 subjects (age 46.7(12.5 years; 8 women). The electric activity was recorded by means of 2 monopolar electrodes applied to each of the SC, RSC and R. The RSC was then anesthetized with xylocaine and the electric activity of SC, RSC and R was recorded after 10 minutes and one hour. The test was repeated using saline instead of xylocaine. The SC, RSC and R exhibited electric activity in the form of pacesetter potentials (PPs) and action potentials (APs). The PPs were monophasic in the SC and triphasic in the RSC and R. The frequency, amplitude and conduction velocity of the waves recorded from the RSC and R had higher readings (p<0.05) than those from the SC. The RSC and R showed a similar frequency and conduction velocity, but the RSC had a higher amplitude (p<0.05). Ten minutes after RSC anesthetization, electric waves were recorded from the SC but not from the RSC or R; electric activity returned one hour after anesthetization. Saline injection of the RSC did not affect the electric activity of the RSC, SC or R. The electric wave pattern and parameters of the RSC and R differed from those of the SC, suggesting that they are evoked by 2 different pacemakers. The similarity in pattern, frequency and conduction velocity of electric waves of RSC and R supposedly denotes that the rectal waves are a continuation of those of the RSC and that both are evoked by a single pacemaker located in the RSC. The higher amplitude of the RSC waves may be due to the thicker RSC musculosa in comparison to that of the SC and R and may by itself be an evidence of the sphincteric function of the RSC.

Adult↗
PubMed2001

Study of the mechanism underlying the difference in motility between the large and small intestine: the "single" and "multiple" pacemaker theory.

The common movement of the small intestine (SI) is peristalsis and of the large intestine (LI) are giant migrating contractions. The mechanism underlying the difference in the type of motility between the SI and LI is yet to be elucidated; the current communication investigated this point. 7 pigs (4 male) were anesthetized, abdomen opened and a balloon-ended catheter was introduced into the right colon through ileotomy. Balloon was filled in increments of 10 ml of saline and the EMG activity of the colonic longitudinal and circular muscle layers was recorded before and after myotomy performed between 2 of the 3 electrodes fixed to the colon. The balloon was then withdrawn, located in the terminal ileum and distended in increments of 2 ml; the ileal EMG activity was registered before and after myotomy done between 2 of the 3 electrodes applied to the ileum. The LI showed slow waves or pacesetter potentials (PPs) and action potentials (APs) which had the same frequency, amplitude and conduction velocity from the 3 electrodes of the same animal. The waves were recorded from the longitudinal and not the circular muscle coat. Upon LI distension, the electric activity increased and was recorded also from the circular muscle. At 40-50 ml distension, the balloon was dispelled to the transverse colon. Electric activity from SI was similar to that of the LI, but was not the same from the 3 electrodes; it diminished aborally. It increased with increasing balloon distension until, at 8-10 ml distension, the balloon moved slowly aborally. Electric waves were recorded proximally but not distally to colonic myotomy, and the balloon moved up to the cut. In the SI, waves were recorded both proximally and distally to the ileal myotomy, and the balloon moved across the cut. The fact that the colonic electric waves displayed the same variables from the 3 electrodes and that they were not recorded distally to the colonic myotomy, would suggest the presence of a "single" colonic pacemaker, probably situated in the cecum. This is in contrast to the hypothesis of the "multiplicity" of the small intestinal pacemakers, which is based on the fact that the electric activity diminished as the waves propagated aborally and on the existence of slow waves distal to the ileal myotomy. The concept of "single" and "multiple" pacemakers explaining the difference in the motility of small from that of large gut needs further studies.

Animals↗
PubMed2001

Transverse folds of rectum: anatomic study and clinical implications.

There are controversies with respect to the location, number, and function of the transverse folds of the rectum (TFR), probably because their physioanatomic aspects have not been fully investigated. The purpose of this communication was to study the anatomic and histologic structure of the TFR aiming at elucidation of their function in the light of their structure. The TFR were studied morphologically and histologically in 18 cadavers (10 male, 8 female) with a mean age of 36.6 +/- 10.4 (SD) years. Barium enema studies were also performed in 36 volunteers (20 male, 16 female; mean age 38.6 +/- 15.2 [SD] years). The number of TFR varied, the commonest findings being two and three. In a few cases, TFR were absent or exceeded three in number. Most folds extended beyond the middle of the rectal lumen; a few were narrow. They were thick at the base and tapered gradually. Microscopically, the TFR contained circular and longitudinal smooth muscle fibers; they were rarely purely mucosal. TFR varied in location dividing the rectum into compartments; an alternating side-to-side arrangement allows for a wavy movement of the stool in the rectum. The wavy movement, compartmental division, and the shelving action of the TFR are suggested to retard stool movement in the rectum so as to allow time for fecal sampling (stool or gas) and for impulses to reach the conscious level to decide whether or not to defecate. Further studies are needed to investigate the role of the TFR in clinical practice.

Adolescent↗
PubMed2001

Effect of pelvic floor muscle contraction on vesical and rectal function with identification of puborectalis-rectovesical inhibitory reflex and levator-rectovesical excitatory reflex.

The effects of pelvic floor muscle contraction on rectal and vesical function were studied in 19 healthy volunteers with the aim of shedding light on some of the hitherto vague aspects of the mechanisms involved in micturition and defecation and their disorders. Rectal and vesical pressures were recorded during puborectalis (PR) and levator ani (LA) muscle stimulation with the rectum or urinary bladder empty and full. Muscle stimulation was effected by needle EMG electrode. The pressure responses to stimulation of the PR and LA muscles were also recorded with these muscles and the rectum and urinary bladder individually anesthetized in 12 of the 19 subjects. The test was repeated using saline instead of xylocaine. PR and LA muscle stimulation produced no pressure response in the empty rectum or bladder. Upon rectal balloon distension with a mean of 156.6+/-34.2 ml of carbon dioxide the mean rectal pressure was 64.6+/-18.7 cm H2O, the subject felt the urge to evacuate and the balloon was expelled to the exterior. On PR muscle stimulation at rectal distension with the above volume, the subject did not feel the urge to evacuate, the rectal pressure was 8.2+/-1.6 cm H2O and the balloon was not expelled. Upon LA stimulation at the same volume, the urge persisted, the rectal pressure was higher and the balloon was expelled. Vesical filling with a mean of 378.2+/-23.6 ml of saline initiated the urge to urinate and elevated the vesical pressure. PR muscle stimulation at this volume aborted the urge and pressure elevation, while LA stimulation caused more elevation of the vesical pressure and spontaneous micturition. Bladder filling with a mean of 423.6+/-38.2 ml produced high vesical pressure and spontaneous urination, both of which were prevented by PR muscle stimulation but not by LA muscle stimulation. Stimulation of the PR and LA muscles during individual anesthetization of the rectum, bladder or PR and LA muscles resulted in no significant rectal or vesical pressure changes. Repetition of the test using saline instead of xylocaine resulted in rectal and vesical pressure responses similar to those without the use of saline. In conclusion, the decline in rectal and vesical responses upon PR muscle contraction indicates a reflex relationship which we term 'puborectalis rectovesical inhibitory reflex'. This reflex is suggested to abort the urge to defecate or urinate. In contrast, LA muscle contraction produced rectal and vesical pressure elevation which is suggested to be mediated through the 'levator rectovesical excitatory reflex'. 'This reflex is probably evoked to promote rectal and vesical evacuation.

Adolescent↗
PubMed2001

Study of the effect of temperature on the rectal function with evidence of thermorectal reflex.

BACKGROUND AND AIMS: Rectal sensation seems to originate from mechanoreceptors which are stimulated by passive rectal filling or active contraction. We investigated the effect of temperature on rectal function. PATIENTS AND METHODS: A balloon was introduced into the rectum of 28 healthy volunteers, filled with 50 ml saline at various temperatures, and rectal pressure was recorded. The test was repeated 30 min and 3 h after rectal anesthetization. RESULTS: Rectal pressure was significantly reduced at 45 degrees and 40 degrees C, showed no change at 37 degrees or 30 degrees C, and was increased at 20 degrees, 10 degrees, and 0 degrees C. At 45 degrees C patients felt rectal pain but no sensation of warmth; at 40 degrees, 37 degrees, and 30 degrees C neither rectal pain nor warm sensation was felt; at 20 degrees C or below rectal pain and cold sensation were perceived. Rectal balloon filling 30 min after anesthetization caused no significant rectal pressure changes or sensation of coldness or warmth; after 3 h, when the anesthetic had waned, the rectal pressure response and sensation were similar to those before anesthetization. CONCLUSIONS: Warm saline appears to cause rectal relaxation and cold saline rectal contraction. Subjects did not perceive sensation of warmth in the rectum but felt cold sensation, which may indicate the presence of cold receptors in the rectal wall. The rectal response to temperature variations is suggested to be reflex in nature as evidenced by its absence on rectal anesthetization. Such reflex, designated "thermorectal reflex," is proposed to mediate the rectal response and is speculated to have clinical significance in rectal dysfunctional and neurogenic disorders.

Adult↗
PubMed2001

Effect of levator ani muscle contraction on urethrovesical and anorectal pressures and role of the muscle in urination and defecation.

OBJECTIVES: To investigate the effect of levator ani muscle (LAM) (the main muscle in the pelvic floor) contraction on the anorectal and urethrovesical pressures and elucidate its role in the mechanisms of defecation and urination. METHODS: In 18 healthy volunteers (10 men and 8 women; mean age 38.6 +/- 10.2 years), the LAM was stimulated to contract by a concentric needle electrode, and the anal, rectal, urethral, and vesical pressure responses were recorded. The test was repeated once after LAM anesthetization with Xylocaine injection and again after saline instead of Xylocaine injection into the LAM. RESULTS: On LAM stimulation, the anal and urethral pressures had a significant decline (both P <0.05), and the rectal and vesical pressures exhibited no significant changes (both P >0.05). The anal, rectal, urethral, and vesical pressures did not show significant changes on stimulation of the anesthetized LAM; after saline injection, the pressure response was similar to that before injection (P >0.05). These results were reproducible. CONCLUSIONS: LAM contraction lowers the anal and urethral pressures and appears to assist in the evacuation process. We therefore propose that the LAM is a muscle of evacuation and that LAM dysfunction could lead to defecation and urination disorders.

Adolescent↗
PubMed2001

Magnetic pudendal neurostimulation: a novel method for measuring pudendal nerve terminal motor latency.

OBJECTIVE: Magnetic stimulation (MS) activates the neuromuscular tissue. This effect was used to develop a novel technique for measuring the pudendal nerve terminal motor latency (PNTML) to the external anal sphincter (EAS) in healthy volunteers and patients with fecal incontinence. METHODS: The PNTML was studied in 42 healthy volunteers (mean age 44.3 years; 30 men, 12 women) and 18 patients with neurogenic fecal incontinence (mean age 42.8 years; 12 men, 6 women) using two techniques in each subject: the conventional intrarectal glove-mounted and MS. In the MS technique, the pudendal nerve was stimulated by a magnetic stimulator and a magnetic coil fixed to the perianal skin at the base of the ischiorectal fossa. Stimulation parameters were set at 70% of maximum intensity, i.e. 175 J/pulse and 40 Hz frequency. The response of EAS to MS was recorded by a surface electrode applied to the perianal skin in the vicinity of the anal orifice. RESULTS: In healthy subjects, the PNTML recorded by MS from the right side (mean 2.2 ms) showed no significant difference from the left PNTML (mean 2.1 ms) and both values did not differ significantly from those recorded by the intrarectal method (right 2.2 ms; left 2.1 ms). In incontinent patients, both the right and left PNTML measured by MS exhibited a significant increase compared to the normal (P<0.05, P<0.05, respectively) but no significant difference if compared to values recorded by the intrarectal route. CONCLUSIONS: The results of measuring the PNTML to the EAS by MS were as accurate as those measured by the intrarectal method. However, the MS method seems to be easier and more convenient to the patient.

Adolescent↗
PubMed2001

Injured external anal sphincter in erectile dysfunction.

The purpose of this study was to investigate the function of the bulbocavernosus muscle in patients with faecal incontinence as a result of injury to the external anal sphincter, and to find out whether faecal incontinence had any role in erectile dysfunction. The study comprised 16 men (age 41.6+/-6.8 years) whose erectile dysfunction and faecal incontinence followed an operation for anal fistula. Erection could not be maintained until ejaculation, which, if it did occur, was not in jets. Ten healthy volunteers acted as controls. The activity of the external anal sphincter and the bulbocavernosus muscle was recorded by electromyography; anal and penile bulb pressures were also recorded. Investigations showed that erectile function was normal. The external anal sphincter was repaired, and faecal control and erectile dysfunction were assessed. Patients were followed up for 19.6+/-3.2 months. The results showed that the bulbocavernosus reflex elicited no response in either the sphincter or the bulbocavernosus muscle. Their activity, recorded by electromyography, as well as anal and bulbar pressures at rest and on voluntary squeeze, and electrostimulation of the external anal sphincter, showed a significant reduction compared to the controls. Sphincteroplasty made the patients continent and restored erectile function and ejaculation to normal. We conclude from the current study that the reduced activity of the bulbocavernosus muscle is probably caused by injury to the external anal sphincter. It is suggested that erectile dysfunction is caused by the failure, during erection, of the contraction of the bulbocavernosus muscle to raise cavernosal pressure above systolic blood pressure. The loss of the rhythmical contractions of the bulbocavernosus muscle is probably why ejaculation did not occur in jets. Repair of the external anal sphincter provided a cure for faecal incontinence and erectile dysfunction. Anorectal disorders are believed to affect erectile function, a relationship that needs further investigation.

Adult↗
PubMed2001

Transmission of rectal electric waves: is it through circular or longitudinal smooth muscle layers or both?

The rectum possesses electric activity in the form of pacesetter (PPs) and action potentials (APs). In recent studies we suggested that the waves are not initiated by the extrarectal autonomic innervation but might be triggered by a 'rectosigmoid pacemaker' and are transmitted in the rectal wall through the rectal musculature and not the enteric nerve plexus. To investigate whether the rectal waves are transmitted through the circular or longitudinal muscle layer, the rectum of 18 mongrel dogs was exposed under anesthesia through an abdominal incision. Three electrodes were applied to the rectal wall (longitudinal muscle layer) and another 3 electrodes to the circular muscle; the latter was exposed by splitting apart the fibers of the longitudinal muscle. Rectal electric activity and pressure were recorded from the 6 electrodes before and after performing individual myotomy of the rectal longitudinal (9 dogs), circular (9 dogs), and then the whole muscle layers (18 dogs). The myotomy was performed proximal to and between the electrodes. Pacesetter (PPs) and action potentials (APs) were recorded from the 3 electrodes on the longitudinal muscle but no waves were registered from those on the circular muscle. After longitudinal muscle myotomy was performed between electrodes 1 and 2, PPs and APs were recorded from electrode 1 but not 2 and 3 and when performed proximally to electrode 1, no waves were registered. The rectal pressure increased concomitantly with occurrence of APs. Circular muscle myotomy effected no change in the rectal electric activity recorded from the 3 electrodes applied to the longitudinal muscle. In total muscle myotomy, the electric waves were recorded from the electrodes proximal but not distal to the myotomy. We propose that the motile activity of the rectal longitudinal muscle is initiated by the electric activity which appears to be triggered by the rectosigmoid pacemaker, while that of the circular muscle fibers is believed to be initiated by the stretch reflex induced by rectal distension. This concept is evidenced not only by the current findings but also by the histologic structure of the rectal musculature being of the unitary type of smooth muscles.

Action Potentials↗
PubMed2001

Study of the mechanism of rectal motility: the 'mass squeeze contraction'.

The motor physiology of the rectum has remained largely obscure, especially concerning the mechanism of rectal motility. In the current communication we tested the possibility of characterizing the mechanism of rectal motility during filling and evacuation through the study of the rectal electric activity in 16 healthy volunteers (mean age 43.6 +/- 10.8 years; 11 men). Two monopolar silver-silver chloride electrodes were introduced per annum and fixed to the rectal mucosa by suction. The rectum was distended in 10 ml increments of water by means of a balloon-ended catheter inserted into the rectum. The rectal pressure was measured by one catheter placed above and a second one below the rectal balloon, and the 2 catheters were connected to 2 strain gauge pressure transducers. Regular triphasic slow waves or pacesetter potentials (PPs) were recorded from the 2 electrodes at rest. PPs were superimposed or followed randomly by action potentials (APs). APs but not PPs were coupled with elevated rectal pressure. Rectal distension with 10 ml of water caused no significant changes of the rectal pressure or EMG activity. Distension with a mean volume of 27.3 +/- 4.7 ml effected a significant increase (p < 0.05) of the rectal electromechanical activity proximally to the balloon and a decrease distally (p < 0.05) to it. With progressive increase of the rectal distension, the electromechanical activity continued to increase proximally and to decrease distally to the balloon, until, at a mean distending volume of 76.3 +/- 3.7 ml, the balloon was dispelled to the exterior. In conclusion, the identification of the modality of rectal motility during defecation was feasible by recording the rectal electromechanical activity. The rectal contraction is suggested to occur in a 'mass squeeze manner' which squeezes the rectal contents aborally into the anal canal. The recognition of the rectal motor modality appears to be important for the understanding of rectal motility disorders. However, further studies are required to confirm these findings.

Action Potentials↗
PubMed2001

The "uninhibited rectum": a cause of fecal incontinence.

OBJECTIVE: The uninhibited (unstable) rectum has been defined as a cause offecal incontinence (FI) in patients with supraconal lesions. In this study, we tested the hypothesis that the uninhibited rectum may be a cause of FI in patients with normal anal pressure and sphincteric mechanism who were considered to have idiopathic FI. METHODS: The study comprised 82 patients (mean age 38.2 +/- 11.2 years; 58 women and 24 men) with idiopathic FI and a control group of 20 healthy volunteers (mean age 36.3 +/- 10.6 years; 14 women and 6 men). Inclusion criteria for FI patients were normal electromyogram of the external anal sphincter and puborectalis muscle, and normal anal sensation, pressure, and endosonography. Rectometry was performed using rectal balloon inflation with CO2 at a rate of 150 cc/min. Rectometrograms were assessed quantitatively and qualitatively. RESULTS: In 79 FI patients, the first rectal sensation was not felt. Urge was perceived at the time of balloon expulsion, which could not be prevented by voluntary sphincteric squeeze. In the remaining 3 patients, the first sensation was perceived but urge coincided with balloon expulsion. Rectometrography showed moderate and gross fluctuations in the tone limb that were not associated with significant changes in intra-abdominal pressure. This contrasted with normal subjects in whom the tone limb exhibited no fluctuations or minor fluctuations that roughly paralleled the intra-abdominal pressure fluctuations. The rectal distension volume at balloon expulsion was significantly lower in FI patients than in controls (P < .05). CONCLUSIONS: These findings suggest that FI can be explained by the fact that the first rectal sensation was that of urge, which was perceived synchronously with balloon expulsion. That is, the balloon had been expelled before the patient could voluntarily squeeze the sphincters to abort expulsion. We postulated that during inflation with small volumes, the rectum did not adapt as in controls, but responded with contractions, which appear to be reflected in the multiple fluctuations in the tone limb. FI in these patients appears to be a consequence of the unstable or uninhibited rectum.

Adolescent↗
PubMed2001

Experimental use of the obturator internus muscle as a functioning pelvic floor muscle in dogs.

OBJECTIVE: To investigate the possibility of using the obturator internus muscle instead of the levator ani as a pelvic floor muscle. DESIGN: Experimental study. SETTING: Teaching hospital, Egypt. ANIMALS: 7 male and 3 female mongrel dogs. INTERVENTIONS: Through a para-anal incision both muscles were exposed; the levator ani was excised and the lower border of the obturator internus was mobilised and sutured to the anorectal junction, the vesical neck, and the vaginal fornix. MAIN OUTCOME MEASURES: Rectal and anal pressures and electromyographic (EMG) activity recorded before and during transposition, and 1, 3, and 6 months later. Histological examination of biopsy specimens taken from the levator ani before, and from the obturator internus before, and 3, 6, and 12 months after, transposition. RESULTS: Stimulation of the levator ani caused anal pressure to decline significantly (p < 0.05). Stimulation of the obturator internus did not change anal pressure before transposition but caused a decline after it. There was EMG activity in the levator ani at rest, but not in the obturator internus before transposition though it was evident by 6 months afterwards. Levator ani consisted of skeletal muscle fibres with smooth muscle fibres in places, whereas the obturator internus consisted of skeletal fibres alone. Six months after operation examination of the obturator internus showed the presence of some smooth muscle fibres. CONCLUSION: These results suggest that the obturator internus might be suitable both anatomically and physiologically to replace the levator ani. However, before it can be suggested as a treatment for levator dysfunction syndrome further experimental studies are necessary.

Anal Canal↗
PubMed2001

Rectal inhibition by inferior rectal nerve stimulation in dogs: recognition of a new reflex--the 'voluntary anorectal inhibition reflex'.

OBJECTIVE: The effect of inferior rectal nerve (IRN) stimulation on the rectum was studied, postulating that nerve stimulation might inhibit rectal contractility and could thus be used in the management of defecation disorders. METHOD: The IRN was exposed through a para-anal incision in 12 dogs (18.2 +/- 3.3 SD kg, seven male, five female) and a cuff-type electrode was applied to the nerve. A balloon introduced into the rectum was filled with saline in increments of 5 ml. The rectal and rectal neck (anal canal) pressures, and the electromyographic (EMG) activity of the external anal sphincter (EAS) and Internal anal sphincter (IAS) were recorded until the balloon was expelled to the exterior. The test was repeated until the expulsion volume was reached, and the IRN was stimulated (pulse width 200 mu/s, charge density 2 to 6 microCi/cm2 per phase). The test was performed again following individual anaesthetization of the EAS and the IAS. RESULTS: At a mean rectal distending volume of 38.3 +/- 2.3 ml, the rectal pressure increased (P < 0.01), rectal neck pressure declined (P < 0.01), the EAS and IAS EMGs disappeared, and the balloon was expelled. IRN stimulation at a distending volume of 38.3 +/- 2.3 ml increased the EMG activity of the EAS, whereas the rectal pressure and IAS EMG did not change (P > 0.05) and the balloon was not expelled. With IRN stimulation at the distending volume of 38.3 +/- 2.3 ml while the EAS was anaesthetized, the rectal pressure increased (P < 0.01), rectal neck pressure diminished, IAS EMG activity disappeared, and the balloon was expelled. Upon repetition of IRN stimulation during anaesthetization of the IAS, the rectal pressure remained high and the balloon was not expelled. CONCLUSION: It is suggested that the EAS produces continence by a twofold action. The EAS prevents IAS relaxation on rectal contraction, with a resulting rectal relaxation. A reflex relationship is postulated to exist between failure of the IAS to relax and rectal relaxation. We call this reflex relationship 'voluntary anorectal inhibition reflex'. Secondly, the EAS mechanically compresses the rectal neck. It seems that contraction of the EAS, which is a striated muscle, mechanically occludes the rectal neck for a few seconds--enough for the rectum to relax in a reflex manner as an effect of the voluntary anorectal inhibition reflex.

Animals↗
PubMed2001

Effect of vaginal distention on vesicourethral function with identification of the vagino-vesicourethral reflex.

PURPOSE: To our knowledge the physiological mechanisms involved in sexual intercourse have not been completely explored. We hypothesized that vaginal distention induced by penile thrusting may affect the function of the bladder and urethra. To verify this supposition we assessed the effect of vaginal distention on vesical and urethral pressure. No relevant reports in the literature were identified. MATERIALS AND METHODS: The response of vesical and urethral pressure to vaginal distention was recorded in 26 healthy women volunteers with a mean age plus or minus standard deviation of 36.7 +/- 9.8 years. A condom was introduced into the vagina and inflated with carbon dioxide in increments of 10 ml. up to 80 ml. Vesical and urethral pressure was measured by a 2-channel microtip catheter connected to a transducer. The vesicourethral pressure response to vaginal distention was also tested after individual anesthetization of the bladder, urethra and vagina. RESULTS: No vesicourethral pressure response was recorded with 10 and 20 ml. of vaginal distention. At 30 and up to 80 ml. of distention bladder pressure decreased and urethral pressure increased (p <0.05). There was no significant difference when the volume of vaginal distention was increased. Mean duration of the pressure response was 4.2 +/- 0.6 seconds. Pressure returned to normal after a latency period of 5.2 +/- 1.1 seconds, although the vagina was continuously distended. Vaginal distention during anesthetization of the bladder, urethra or vagina did not evoke a pressure response. CONCLUSIONS: The vesicourethral response to the inserted condom, which by inflation adopts the shape of the erect penis, seems to simulate the response of the vagina when it is distended by the erect penis during coitus. The constant vesicourethral pressure response to vaginal distention postulates a reflex relation, which we call the vagino-vesicourethral reflex. This reflex is apparently evoked during coitus, leading to momentary vesical dilatation and increased urethral sphincter activity, which most likely acts to prevent urinary leakage during coitus. Reflex disorders may explain urinary leakage during coitus in some neuropathic conditions.

Adult↗