Study of the binding of motilin to the membranes of enterocytes from rabbit jejunum

Effects of two methods of reconstruction of digestive tract after total gastrectomy on gastrointestinal motility in rats

AIM: To compare the effects of Roux-en-Y and jejunum interposition reconstruction procedures after total gastrectomy on intestinal motility.

METHODS: Fifty male Sprague-Dawley rats were randomly divided into 5 groups: the control group (C), the laparotomy group (L), the jejunal transection group (JT) where the jejunum was transected 10 cm distal from the Treitz ligament and anastomosed, the Roux-en-Y group (RY) and the jejunal interposition group (JI) after total gastrectomy. To evaluate intestinal transit, the animals were given 0.1 ml Evans Blue solution through an orogastric tube. The rats were executed by CO₂ inhalation 30 minutes later and the intestinal transmit was determined as the distance between the site of esophageojejunal anastomosis and the most distal site of small intestine colored with blue.

RESULTS: One month after operation, the body weight of rats among JI and RY were almost identical (274.6 ± 9.5 vs 270.4 ± 10.6, P > 0.05), but were significantly lighter than those of JT and L group. Four months after the operation, the body weight in the JI group increased compared to the preoperative level (345.2 ± 15.7 g vs 299.5 ± 8.3 g, P < 0.01). However, the body weight of RY group decreased compared to preoperative (255.1 ± 11.3 g vs 295.0 ± 12.0 g, P < 0.01). The difference was more significant at six months postoperative. Small bowel transmit time in RY was slower than that in JI group and C group (P < 0.01).

CONCLUSION: Changes of body weight and intestinal motility in JI group are less influenced than in RY group.

Study of serotonin interactions with brush border membrane of rabbit jejunum enterocytes

Recent studies have demonstrated that serotonin (5-hydroxytryptamine, 5-HT) may interact with either specific receptors or with a specific transporter that takes up 5-HT in the gastrointestinal tract. The purpose of the present work was to study the 5-HT interactions with brush border membrane from rabbit jejunum enterocytes. The results obtained showed that 5-HT did not seem to be transported by any specific system of transport in brush border membrane vesicles. Nevertheless, [3H]5-HT seemed to bind specifically to this membrane. The kinetic analysis indicated a saturable and dissociable specific binding with a dissociation constant K(D)=14x10(-9) M. The saturation studies with [3H]5-HT indicated the presence of one specific site in the brush border membrane. The results of displacement of [3H]5-HT specific binding from the brush border membrane showed that both unlabelled 5-HT and unlabelled GR113080 ([1-[(2-methyl sulphonyl) amino] ethyl-4-piperidinyl] methyl-1-methyl-1H-indole-3-carboxylate), a specific competitive antagonist of 5-HT(4) receptors, inhibited the specific binding of [3H]5-HT to this membrane.