Anourethral reflex. Description of a reflex and its clinical significance: preliminary study

Shafik, Ahmed

doi:10.1038/sc.1992.57

Cited by 13 publications

(5 citation statements)

References 8 publications

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“…Moreover, it seems that the contraction of the cavernosus muscles indirectly effects urethral sphincter contraction. Previous studies demonstrate that anal sphincteric contraction evokes the ano-urethral reflex with a resulting external urethral sphincter contraction [18]. Therefore, cavernosal muscles' contraction induces contraction of both the anal and urethral sphincters.…”

Section: Role Of Cavernoso-anal Reflex During Sexual Intercoursementioning

confidence: 96%

The cavernoso-anal reflex: response of the anal sphincters to cavernosus muscles' stimulation

Shafik¹,

Shafik²,

Shafik³

et al. 2006

Asian J Andrology

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Section: Role Of Cavernoso-anal Reflex During Sexual Intercoursementioning

confidence: 96%

The cavernoso-anal reflex: response of the anal sphincters to cavernosus muscles' stimulation

Shafik¹,

Shafik²,

Shafik³

et al. 2006

Asian J Andrology

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“…In addition to voluntarily contracting or relaxing while the other does not, both of these muscles reflexively contract or relax simultaneously (53). Electophysiological evidence demonstrated that basal activity of the external urethral sphincter was altered by electric stimulation of the EAS in healthy volunteers (52). In addition, vigorous distension of anal sphincter led to inhibition of urethra and anal sphincter activity in most spinal cord-injured patients (48).…”

Section: Discussionmentioning

confidence: 99%

Acute anal stretch inhibits NMDA-dependent pelvic-urethra reflex potentiation via spinal GABAergic inhibition in anesthetized rats

Chen

Huang

Kao

et al. 2008

American Journal of Physiology-Renal Physiology

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The impact of acute anal stretch on the pelvic-urethra reflex potentiation was examined in urethane-anesthetized rats by recording the external urethra sphincter electromyogram activity evoked by the pelvic afferent stimulation. Test stimulation (1 stimulation/30 s) evoked a baseline reflex activity with a single action potential that was abolished by gallamine (5 mg/kg iv). On the other hand, the repetitive stimulation (1 stimulation/1 s) induced spinal reflex potentiation (SRP) that was attenuated by intrathecal 6-cyano-7-nitroquinoxaline-2,4-dione (a glutamatergic ␣-amino-3-hydroxy-5-methyl-4-isoxazoleproprionat receptor antagonist, 100 M, 10 l) and D-2-amino-5-phosphonovalerate [a glutamatergic N-methyl-D-aspartate (NMDA) antagonist, 100 M, 10 l]. Acute anal stretch using a mosquito clamp with a distance of 4 mm exhibited no effect, whereas distances of 8 mm attenuated and 12 mm abolished the repetitive stimulation-induced SRP. Intrathecal NMDA (100 M, 10 l) reversed the abolition on SRP caused by anal stretch. On the other hand, pretreated bicuculline [␥-aminobutyric acid (GABA) A receptor antagonist, 100 M, 10 l] but not hydroxysaclofen (GABA B receptor antagonist) counteracted the abolition on the repetitive stimulation-induced SRP caused by the anal stretch. All of the results suggested that anal stretch may be used as an adjunct to assist voiding dysfunction in patients with overactive urethra sphincter and that GABAergic neurotransmission is important in the neural mechanisms underlying external urethra sphincter activity inhibited by anal stretch. spinal cord; voiding dysfunction; glutamate; bicuculline; hydroxysaclofen THE MECHANISM INVOLVED IN micturition, which is the result of coordination between bladder detrusor and outlet, is intricate. Both elements, the detrusor and outlet, maintain a sound cycle of storage and evacuation that is controlled by a group of reflex and voluntary actions (54). During the storage phase of a micturition cycle, detrusor relaxes and urethra contracts to produce continence; while the detrusor contracts, with sphincter relaxes to void urine during the evacuation phase. Inhibition of external urethra sphincter (EUS) activity during evacuation is essential for sufficient bladder emptying (18, 49). The absence of suppression on EUS activity during voiding is one feature of the pathological condition referred to as detrusor-sphincter dyssynergia (51). Such a dyssynergic sphincter contraction results in high intravesical pressure and residual urine. Therefore, to achieve near-normal voiding function in patients with detrusor-sphincter dyssynergia, outlet resistance should be reduced.Arising from the puborectalis muscle, EUS innervated by the perineal branch of the pudendal nerve and external anal sphincter (EAS) innervated by the rectal branch of the pudendal nerve are both striated skeletal muscles that contract and relax voluntarily. A study investigating the coordination between the EUS and EAS muscles demonstrated these muscles shared in reflex actions as in dilatation a...

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“…We calculated the latency which is the period between the start of iced saline infusion into the rectum and the onset of the rectal tone response. The latency was measured by the switch-inflation apparatus (Avicina Medical Instruments, Cairo, Egypt) [19] .…”

Section: Methodsmentioning

confidence: 99%

Effect of Cooling on the Rectal Tone

Shafik

Sibai²,

Shafik³

et al. 2007

Eur Surg Res

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Objectives: It has been claimed that recognizable organized sensory nerve endings could not be detected in the rectal wall. Hence the identification of cold receptors sensitive to cold temperature in the rectal wall has so far not been reported in the literature. We investigated the hypothesis that rectal cooling effected an increase of the rectal tone. Methods: Twenty-eight healthy volunteers (18 men, 10 women, age 26–50 years) were studied. The rectal wall tone was assessed by the barostat system during infusion of normal saline at 30°C and at 4°C. The test was repeated after rectal anesthetization with lidocaine. Results: The rectal tone on rectal saline infusion showed no response at a temperature of 30°C, and asignificant increase (p < 0.05) at 4°C. The latency measured by the switch-inflation apparatus recorded a mean of 15.3 ± 1.2 ms. Iced saline infusion into the anesthetized rectum effected no significant change in the rectal tone. Conclusions: The current study has demonstrated that rectal infusion of iced saline produced an increase of the rectal tone. This effect is suggested to be a reflex and mediated through the ‘rectal cooling reflex’. The reflex is suggested to act as an investigative tool in the diagnosis of rectal motile disorders provided further studies are performed.

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Anourethral reflex. Description of a reflex and its clinical significance: preliminary study

Cited by 13 publications

References 8 publications

The cavernoso-anal reflex: response of the anal sphincters to cavernosus muscles' stimulation

The cavernoso-anal reflex: response of the anal sphincters to cavernosus muscles' stimulation

Acute anal stretch inhibits NMDA-dependent pelvic-urethra reflex potentiation via spinal GABAergic inhibition in anesthetized rats

Effect of Cooling on the Rectal Tone

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