scholarly journals All together now: from pacemakers to gastric peristalsis

2006 ◽  
Vol 571 (1) ◽  
pp. 1-1 ◽  
Author(s):  
Marcello Costa
Keyword(s):  
2009 ◽  
Vol 296 (6) ◽  
pp. G1180-G1190 ◽  
Author(s):  
Abigail S. Forrest ◽  
Grant W. Hennig ◽  
Sari Jokela-Willis ◽  
Chong Doo Park ◽  
Kenton M. Sanders

Gastric emptying depends on functional coupling of slow waves between the corpus and antrum, to allow slow waves initiated in the gastric corpus to propagate to the pyloric sphincter and generate gastric peristalsis. Functional coupling depends on a frequency gradient where slow waves are generated at higher frequency in the corpus and drive the activity of distal pacemakers. Simultaneous intracellular recording from corpus and antrum was used to characterize the effects of PGE2 on slow waves in the murine stomach. PGE2 increased slow-wave frequency, and this effect was mimicked by EP3, but not by EP2, receptor agonists. Chronotropic effects were due to EP3 receptors expressed by intramuscular interstitial cells of Cajal because these effects were not observed in W/W V mice. Although the integrated chronotropic effects of EP3 receptor agonists were deduced from electrophysiological experiments, no clear evidence of functional uncoupling was observed with two-point electrical recording. Gastric peristalsis was also monitored by video imaging and spatiotemporal maps to study the impact of chronotropic agonists on propagating contractions. EP3 receptor agonists increased the frequency of peristaltic contractions and caused ectopic sites of origin and collisions of peristaltic waves. The impact of selective regional application of chronotropic agonists was investigated by use of a partitioned bath. Antral slow waves followed enhanced frequencies induced by stimulation of the corpus, and corpus slow waves followed when slow-wave frequency was elevated in the antrum. This demonstrated reversal of slow-wave propagation with selective antral chronotropic stimulation. These studies demonstrate the impact of chronotropic agonists on regional intrinsic pacemaker frequency and integrated gastric peristalsis.


1989 ◽  
Vol 67 (9) ◽  
pp. 1029-1032 ◽  
Author(s):  
William A. Mersereau ◽  
E. John Hinchey

Inhibition of prostaglandin synthesis together with vagally mediated peristaltic contractions are essential if mucosal injury is to occur in the stomach of indomethacin-treated rats. The neomycin group of antibiotics has been shown to interfere with acetylcholine release. Agents blocking peristalsis have been demonstrated to prevent mucosal injury. We postulated that neomycin might inhibit peristalsis and prevent lesion formation. The effect of oral neomycin and bacitracin on gastric wall tone and peristaltic response to indomethacin were assessed and related to the lesion score. Bacitracin had no effect on either response and severe injury occurred. Neomycin did not block the tonal response to indomethacin but abolished peristalsis and no injury occurred. Induction of peristalsis with insulin in neomycin–indomethacin treated rats restored mucosal injury. It is concluded that neuromuscular blockade by neomycin prevented mucosal lesions by preventing peristalsis and not by impairing the ability of indomethacin to inhibit prostaglandin synthesis.Key words: stomach, ulcer, etiology, indomethacin, peristalsis.


2010 ◽  
Vol 5 (4) ◽  
pp. 330-336 ◽  
Author(s):  
Hiroyuki Kozu ◽  
Isao Kobayashi ◽  
Mitsutoshi Nakajima ◽  
Kunihiko Uemura ◽  
Seigo Sato ◽  
...  

DICP ◽  
1989 ◽  
Vol 23 (3) ◽  
pp. 203-208 ◽  
Author(s):  
Edgar R. Gonzalez ◽  
Surinder K. Kallar

Regurgitation of gastric contents with subsequent aspiration into the lungs contributes significantly to morbidity and mortality in surgical and nonsurgical patients. The consequences of aspiration pneumonitis depend on the volume and the acidity of the aspirate, and the presence of particulate and bacteria in the aspirate. The occurrence of aspiration pneumonitis may be prevented by correction of risk factors, careful monitoring, and appropriate airway management. The goal of aspiration pneumonitis prophylaxis is to minimize pulmonary complications by controlling risk factors for gastric regurgitation, which include gastric pH ≤ 2.5, gastric volume >25 mL, lower esophageal sphincter incompetence, and delayed peristalsis. Prophylactic techniques include nasogastric decompression, acid neutralization, acid suppression, and increased gastric peristalsis. The ability of drugs to alter risk factors does not guarantee that aspiration will not occur, but it does reduce the likelihood of secondary respiratory complications. The ideal prophylactic agent should consistently reduce all risk factors, produce a prompt and sustained response, and possess few adverse effects and drug interactions.


JAMA ◽  
1922 ◽  
Vol 79 (16) ◽  
pp. 1281 ◽  
Author(s):  
WALTER C. ALVAREZ

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