A study of the origin of the electric activity of the rectum: Is it neurogenic or myogenic?

Shafik, Ahmed

doi:10.1038/sj.sc.3100611

Cited by 26 publications

(24 citation statements)

References 3 publications

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“…The rectal pressure elevation in association with APs is in accord with previous studies (Shafik, 1993b(Shafik, , 1994(Shafik, , 1998. These studies have also shown that the frequency and amplitude of the APs as well as the concomitant rectal pressure elevation increased with increase of the rectal distending volume.…”

Section: Discussionsupporting

confidence: 90%

“…Preceding studies (Shafik, 1993b(Shafik, , 1994(Shafik, , 1998Shafik et al, 1999), have suggested the presence of a rectosigmoid pacemaker which seems to initiate the rectal electric activity. The current study has shown that the waves spread caudad along the rectal longitudinal muscle coat.…”

Section: Discussionmentioning

confidence: 97%

“…It was proposed that rectal electric activity disorders might lead to rectal dysmotility and defecation disorders (Shafik, 1993c(Shafik, , 1995a. A preceding study (Shafik, 1998), has demonstrated that rectal electric waves persisted after bilateral pelvic ganglionectomy but exhibited a 'rectoarrhythmic pattern'. It was suggested that the waves are not initiated by, but may be under the control of, extrarectal autonomic innervation.…”

Section: Introductionmentioning

confidence: 98%

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Transmission of Rectal Electric Waves: Is it through Circular or Longitudinal Smooth Muscle Layers or Both?

Shafik

El-Sibai

2001

Archives of Physiology and Biochemistry

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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.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

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Transmission of Rectal Electric Waves: Is it through Circular or Longitudinal Smooth Muscle Layers or Both?

Shafik

El-Sibai

2001

Archives of Physiology and Biochemistry

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“…A recent study of the rectal electric activity was done to investigate whether the origin of these waves is neurogenic or myogenic (26), and it was suggested that these waves are not initiated by, but may be under the control of, the extrarectal autonomic innervation.…”

Section: Resultsmentioning

confidence: 99%

Transcutaneous electrohepatogram in humans

Shafik

1999

Front Biosci

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We could recently characterize a normal "electrohepatogram" (EHG) in a canine model. It consisted of monophasic positively deflected slow waves or pacesetter potentials (PPs). A "dysrhythmic EHG" was produced when the liver was insulted by hepatic vessel clamping or liver irradiation.The postulation that electrohepatography might act as an investigative tool in liver diseases prompted the author to develop the EHG percutaneously in humans. 23 healthy volunteers (16 men, 7 women; mean age 38.6 years) and 13 patients (8 men, 5 women; mean age 34.2 years) with huge supraumbilical ventral hernia were studied. The liver was exposed during the ventral hernia repair and 3 electrodes were sutured to the liver capsule. The optimal position for percutaneous recording was identified. The 3 electrodes were placed, 5 cm apart, on a transverse line, parallel to and 1.5-2 cm below, the costal margin. PPs were recorded from the 3 electrodes applied directly to the liver and from those applied to the skin. The wave was monophasic and positively deflected with a mean frequency of 8.3 cycle/s and amplitude of 56.5 µV. The PPs had the same frequency and amplitude from the 3 electrodes applied to the same subject. The percutaneously recorded waves were identical with those recorded directly from the liver. A percutaneous EHG could be characterized for the normal liver in humans. It might show changes in liver diseases and thus act as an investigative tool in the diagnosis of such conditions.

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“…The electric waves seem generated by the interstitial cells of Cajal (ICCs) and mediate the contractile activity of the smooth musculature [5,7,11,12]. Meanwhile, the contraction of the prostatic smooth fibers may be responsible for the urethral pressure increase associated with the APs [10].…”

mentioning

confidence: 99%

Identification of C-Kit-Positive Cells in the Human Prostate: The Interstitial Cells of Cajal

Shafik

El-Sibai

2005

Archives of Andrology

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A study of the origin of the electric activity of the rectum: Is it neurogenic or myogenic?

Cited by 26 publications

References 3 publications

Transmission of Rectal Electric Waves: Is it through Circular or Longitudinal Smooth Muscle Layers or Both?

Transmission of Rectal Electric Waves: Is it through Circular or Longitudinal Smooth Muscle Layers or Both?

Transcutaneous electrohepatogram in humans

Identification of C-Kit-Positive Cells in the Human Prostate: The Interstitial Cells of Cajal

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