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Aim: To investigate whether 5-hydroxytryptamine (serotonin; 5-HT) is involved in mediating abnormal motor activity in dogs after cisplatin administration., Methods: After the dogs had been given a 2-wk recovery period, all of them were administered cisplatin, and the motor activity was recorded using strain gauge force transducers. Blood and intestinal fluid samples were collected to measure 5-HT for 24 h. To determine whether 5-HT in plasma or that in intestinal fluids is more closely related to abnormal motor activity we injected 5-HT into the bloodstream and the intestinal tract of the dogs., Results: Cisplatin given intravenously produced abnormal motor activity that lasted up to 5 h. From 3 to 4 h after cisplatin administration, normal intact dogs exhibited retropropagation of motor activity accompanied by emesis. The concentration of 5-HT in plasma reached the peak at 4 h, and that in intestinal fluids reached the peak at 3 h. In normal intact dogs with resection of the vagus nerve that were administered kytril, cisplatin given intravenously did not produce abnormal motor activity. Intestinal serotonin administration did not produce abnormal motor activity, but intravenous serotonin administration did., Conclusion: After the intravenous administration of cisplatin, abnormal motor activity was produced in the involved vagus nerve and in the involved serotonergic neurons via another pathway. This study was the first to determine the relationship between 5-HT and emesis-induced motor activity.

Background: Traditional Japanese medicine, known as Kampo medicine, consists of mixtures of several medicinal herbs widely used to treat upper gastrointestinal disorders in Japan. Rikkunshito, one of these medicines, has not been evaluated with respect to its influence on gastrointestinal motor activity. We investigated the effect of rikkunshito on upper gastrointestinal motility and plasma ghrelin concentrations in conscious dogs., Methods: Contractile response to intragastric administration of rikkunshito was studied via surgically implanted force transducers. A powdered extract of rikkunshito (1.3, 2.7, and 4.0 g) dissolved in water was administered into the stomachs of normal and vagotomized dogs before feeding and gastric emptying was evaluated. Several inhibitors of gastrointestinal motility (atropine, hexamethonium, and ondansetron) were injected intravenously before intragastric administration of rikkunshito. Plasma acylated ghrelin levels after intragastric administration of rikkunshito were measured., Results: In a fasting state, intragastric administration of rikkunshito induced phasic contractions in the duodenum and jejunum in normal dogs. Rikkunshito-induced contractions were inhibited by atropine, hexamethonium and ondansetron. In vagotomized dogs, rikkunshito induced phasic contractions, similar to normal dogs. Gastric emptying was accelerated by intragastric administration of rikkunshito in a dose-dependent manner. The plasma acylated ghrelin level 150 min after intragastric administration of 4.0 g of rikkunshito was significantly higher than the control value., Conclusions: Intragastric administration of rikkunshito stimulates gastrointestinal contractions in the interdigestive state through cholinergic neurons and 5-HT type 3 receptors. Moreover, rikkunshito increases plasma acylated ghrelin levels. Rikkunshito may alleviate gastrointestinal disorders through its prokinetic effects.

Background and Aims: The objective of this study is to compare the postoperative motility between hand-sewn end-to-end anastomosis and functional end-to-end anastomosis., Methods: Fifteen conscious dogs were divided into three groups: normal intact dog group, end-to-end anastomosis group (EE), and functional end-to-end anastomosis group (FEE). In the EE and FEE groups, the dogs underwent a transection of the jejunum 30 cm distal to the Treitz ligament and anastomosis in each method. To compare the gastrointestinal motility, the time to the appearance and the rate of propagation of interdigestive migrating motor contractions (IMC) across the anastomosis, as well as the motility index (MI) at the oral and anal sides of the anastomosis, were measured using strain gauge force transducers. Furthermore, the histological examination of intrinsic nerve fibers was evaluated., Results: The time to the appearance of propagation of IMC in the EE and FEE was not significantly different. The propagation rates of IMC in the EE and FEE completely recovered within 4 weeks of the surgery. The MI in the EE and FEE was not significantly different. In addition, no continuity of intrinsic nerve fibers across the anastomosis could be identified in either group., Conclusions: In the present study, there are no significant differences between the EE and FEE with regard to the time of the appearance and the rate of propagation of IMC. These results suggest that the effect of functional end-to-end anastomosis on postoperative motility is not different from that of hand-sewn end-to-end anastomosis.

Monosodium l-glutamate (MSG) is a substance known to produce the umami taste. Recent studies indicate that MSG also stimulates a variety of activities in the gastrointestinal tract through its receptor in the gut, but no study has reported the activity in conscious large experimental animals. The aim of our study was to investigate whether direct intragastric MSG stimulates gut motility and to identify the mechanism in conscious dogs. Contractile response to intraluminal injection of MSG was studied in the fed and fasted states by means of chronically implanted force transducers. MSG (5, 15, 45, and 90 mM/kg) dissolved in water was injected into the stomach and duodenum in normal and vagotomized dogs. MSG solution was administered into the stomach before feeding, and gastric emptying was evaluated. Several inhibitors of gastrointestinal motility (atropine, hexamethonium, and granisetron) were injected intravenously before MSG administration to the stomach. The effect of MSG was investigated in Pavlov (vagally innervated corpus pouch), Heidenhain (vagally denervated corpus pouch), and antral pouch (vagally innervated) dogs. Upper gut motility was significantly increased by intragastric MSG but not significantly stimulated by intraduodenal MSG. Intragastric MSG (45 mM/kg) stimulated postprandial motility and accelerated gastric emptying. MSG-induced contractions were inhibited by truncal vagotomy, atropine, hexamethonium, and granisetron. Gut motility was increased by intrapouch injection of MSG in the Pavlov pouch, but it was not affected in the Heidenhain or antral pouch dogs. We conclude that intragastric MSG stimulates upper gut motility and accelerates gastric emptying. The sensory structure of MSG is present in the gastric corpus, and the signal is mediated by the vagus nerve.

The objective of this study was to describe the correlation between changes in colonic motility and defecatory disorders in four experimental canine models, with an emphasis on denervation. Therefore, we constructed a model by dividing 20 healthy mongrel dogs into four groups, i.e. control, denervation, transection and anterior resection of the rectum (AR) (denervation plus transection), and focused on the correlation between colonic motility and defecatory disorders by counting the colonic migrating motor complexes (CMMCs) and colonic non-migrating motor complexes (CNMCs). Gastrointestinal and colonic contractile activities were continuously recorded on a computer with strain gauge force transducers. The dogs' feces were checked daily, and their consistency was recorded as normal, semisolid, or watery. Compared with the control group, the transection group showed elongation of the propagation time (P < 0.05), and the mean motility index of colonic contractile activity at C4 and C5 in the denervation group was greater than that in the control group (P < 0.05). The AR group showed three features of colonic motility: (i) elongation of the mean CMMC cycle (P < 0.05); (ii) shortening of the propagation time (P < 0.05); and (iii) increment of the number of CNMCs. Concerning fecal consistency, the AR group only showed watery diarrhoea. In conclusion, we revealed the existence of a correlation between defecatory disorders and changes in colonic motility. Increased knowledge among colorectal surgeons of the changes in colonic motility that occur following colorectal surgery is very important and could lead to the curtailment of defecatory disorders among patients.

Objective: To evaluate the effects of distal subtotal gastrectomy with preservation of the celiac branch of the vagus nerve on gastrointestinal function., Summary Background Data: The operative procedure of distal subtotal gastrectomy with preservation of the celiac branch of the vagus nerve is now in the spotlight in Japan with the goal of finding a function-preserving surgical technique. However, there has been no analysis of the effect of this type of surgery on gastrointestinal function. In this article, we describe the results of a fundamental experiment on distal subtotal gastrectomy with preservation of the celiac branch of the vagus nerve., Methods: Twenty conscious dogs were divided into 2 groups, each subdivided into 2 groups of 5: a normal intact dog group (NG) divided into 2 groups, with preservation (PNG) and resection (RNG; these dogs were truncally vagotomized including transaction of the celiac branch) of the celiac branch, and a gastrectomy dog group (GG) divided into 2 groups, with preservation (PGG) and resection (RGG) of the celiac branch. The motility of the dogs was recorded using strain gauge force transducers. The effects of the preservation of the celiac branch of the vagus nerve on gastrointestinal motility, gastric emptying, and pancreatic insulin release were evaluated., Results: The motility index of gastrointestinal motility with preservation of the celiac branch was higher than the motility index with resection of the celiac branch in fasted and fed of NG and GG. In gastric emptying, significant differences were found between the PNG and RNG but not between the PGG and RGG. In the fasted state for 80 minutes of the PNG and PGG, the serum insulin concentration reached a peak during the early phase III at 20 minutes in the gastric body and the antrum., Conclusions: This study has shown that it is effective to preserve the celiac branch of the vagus nerve for gastroduodenal motility, gastric emptying, and pancreatic insulin release after a gastrectomy.

Background To investigate neural regulation at the ileocecal junction (ICJ) and motility changes after ileocecal resection (ICR). Previous studies showed normal basal motility at the ICJ directly by force transducers in dogs, but these observations were limited to normal contractile activity. Methods Continuous strain gauge recordings of stomach, terminal ileum, ileocecal sphincter (ICS), and colon were performed in dogs. The dogs were divided into four groups, namely control (CONT), extrinsic denervation at ICJ (ED), intrinsic denervation at ICJ (ID), and ICR groups. Colonic activity was recorded 2 h before a meal, in the early postprandial period (first 2 h), and in the late postprandial period (4-6 h after a meal). The meal lasted 5 min. Key Results Motility index was significantly increased at the ICS ( P = 0.0056) and proximal colon ( P = 0.0059) after feeding. However, such changes were not observed in the ED and ID groups. The amplitude of contractions at proximal colon in the interdigestive state was significantly decreased by ED. In the ID and ICR groups, the numbers of nonmigrating contractions were significantly decreased ( P < 0.05), and colonic migrating motor complex (CMMC) ratio was significantly higher than that of the CONT group ( P < 0.001). The dogs in these two groups had diarrhea. Conclusions & Inferences Gastrocolonic response at the ICJ may require both intrinsic and extrinsic innervation. When ID was performed, CMMC ratio increased. As a result, intraluminal water absorption may have decreased. ID may be one of the causes of diarrhea after ICR. [ABSTRACT FROM AUTHOR]