Although bombesin (BN) regulates colonic motility, the associated mechanism of action remains unclear. The objective of this study was to investigate the effect of BN on colonic motility using isolated rat colon. An isolated rat colon was perfused with Krebs solution via the superior mesenteric artery. Intraluminal pressure was measured via microtip catheter pressure transducers at both proximal and distal portions of the isolated colon. After a control period, BN was administered intraarterially in concentrations of 13, 26, 130, and 260 pM. After pretreatment with hexamethonium (10-3 M), atropine (10-5 M), or tetrodotoxin (10-6 M), BN was administered at a concentration of 260 pM (proximal colon) or 130 pM (distal colon); intraluminal pressure was then monitored. Changes in motility were expressed as the percentage change of motility index (MI) over the basal period. As a result, BN increased colonic motility and a dose-dependent increase in proximal colonic motility was observed. The stimulant effect of BN was almost completely abolished by atropine and tetrodotoxin at both the proximal and distal colon. However, BN was not inhibited by hexamethonium at both the proximal and distal colon. Therefore, the stimulant action of BN may be mediated by local cholinergic muscarinic receptors.

Pneumatosis cystoides intestinalis (PCI) is a rare condition characterized by multiple intramural pockets of gas filled cysts in the intestinal wall. PCI is usually found incidentally on an imaging study. Many different causes of PCI have been suggested, including mechanical, pulmonary, and bacterial causes. Treatment is usually conservative, including oxygen and antibiotic therapy. We report on two cases of PCI, without symptoms, in a 62-year-old male and a 72-year-old male. Computed tomography showed numerous, small, round, and air densities on the sigmoid colon. Colonoscopy showed numerous, variable-sized, sessile polypoid, balloon-like distended, and protruding subepithelial masses covered with normal colonic mucosa on the sigmoid colon. We observed that when the cyst was stuck with a needle, the size of the cyst was reduced and showed a flat termination. Therefore, we made a diagnosis of PCI and report on the case with references.