Effects of Caffeine on Gastrointestinal Myoelectric Activity and Colonic Spike Activity in Dogs

Abo, Masaki

doi:10.1080/003655200750023921

Cited by 16 publications

(13 citation statements)

References 26 publications

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“…The APs, thus, appear to be responsible for the rectal motile activity (Shafik, 1994(Shafik, , 1995Shafik et al, 1995;Kauer et al, 1999;Abo et al, 2000). The current and previous studies (Shafik, 1994(Shafik, , 1995Shafik et al, 1995;Kauer et al, 1999;Abo et al, 2000) have demonstrated that APs follow, or are superimposed on, the PPs. The function of the PPs is not exactly known (Kerremans, 1968;Julia et al, 1999;Kauer et al, 1999;Abo et al, 2000).…”

Section: Discussionmentioning

confidence: 50%

“…The current and previous studies (Shafik, 1994(Shafik, , 1995Shafik et al, 1995;Kauer et al, 1999;Abo et al, 2000) have demonstrated that APs follow, or are superimposed on, the PPs. The function of the PPs is not exactly known (Kerremans, 1968;Julia et al, 1999;Kauer et al, 1999;Abo et al, 2000). We suggest that the PPs initiate and pace the APs in terms of frequency and direction (Shafik, 1994(Shafik, , 1995Shafik et al, 1995).…”

Section: Discussionmentioning

confidence: 80%

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Study of the Mechanism of Rectal Motility: The ‘Mass Squeeze Contraction’

Shafik

El-Sibai²,

Mostafa³

et al. 2001

Archives of Physiology and Biochemistry

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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.

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Section: Discussionmentioning

confidence: 50%

Section: Discussionmentioning

confidence: 80%

Study of the Mechanism of Rectal Motility: The ‘Mass Squeeze Contraction’

Shafik

El-Sibai²,

Mostafa³

et al. 2001

Archives of Physiology and Biochemistry

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“…Its effects on the colon are found to be comparable to those of a 1,000 kCal meal. Abo et al, 11 in 2000, showed that an intravenous injection of a caffeine solution, at doses of 125 and 250 mg, in conscious hound dogs resulted in an increase in the myoelectric spike activity of the ascending colon, in a dose-dependent pattern.…”

Section: Discussionmentioning

confidence: 98%

Effects of Caffeine on Anorectal Manometric Findings

Lohsiriwat

Kongmuang

Leelakusolvong

2008

Diseases of the Colon &Amp; Rectum

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“…The mechanism of rectal motility is not yet fully elucidated (Schafer et al, 1996;Cortesini et al, 1995). Electric activity could be recorded from different parts of the gut including the stomach (Kauer et al, 1999;Levanon & Chen, 1998), small (Aube et al, 1999;Medeiros et al, 1997) and large gut (Abo et al, 2000;Julia et al, 1999) and liver (Shafik, 2000). It occurs in the form of slow waves or pacesetter potentials (PPs) and fast activity spikes or action potentials (APs).…”

Section: Introductionmentioning

confidence: 98%

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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Effects of Caffeine on Gastrointestinal Myoelectric Activity and Colonic Spike Activity in Dogs

Abstract: Caffeine increases spike activity in the colon, and its effect may be dose-dependent. Gastric and jejunal slow waves are not affected by caffeine.

Cited by 16 publications

References 26 publications

Study of the Mechanism of Rectal Motility: The ‘Mass Squeeze Contraction’

Study of the Mechanism of Rectal Motility: The ‘Mass Squeeze Contraction’

Effects of Caffeine on Anorectal Manometric Findings

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

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