The Influence of Jejunal Continuous Administration of Glucose, Amino Acids, Fat Emulsion and Saline Solution on the Gastrointestinal Motility and Portal Blood Flow in Conscious Dogs

Changes in gastrointestinal motility and portal blood flow (PBF) by jejunal continuous administration of nutrients and saline solutions were experimentally evaluated in conscious dogs. An electromagnetic flowmeter probe was attached to the portal vein by laparotomy in seven adult dogs under general anesthesia, so that the full circumference of the vein would be covered by it. Bipolar silver electrodes were sewn onto the stomach and small intestine. After recovery, electromyograms (EMGs) of the digestive tract and PBF were recorded for 3 hours before infusion of the nutrients and after 3 hours of their infusion. The nutrients were infused as follows, so that ingestion rate of calorie of every nutrient infused would be 30 kcal/h；10% fat emulsion (FAT), 10% glucose (GLU), and 10% amino acids preparation (AA) were infused at 30 ml/h, 75 ml/h, and 75 ml/h, respectively. Three saline solutions (NaCl), i.e., 0.9, 1.8, and 2.7% solutions, were prepared, and infused at 30 ml/h and 75 ml/h. EMGs of the digestive tract, which were taken for evaluating gastrointestinal motility, revealed that irregular waves were increased and the frequency of migrating myoelectric complex (MMC) was suppressed by infusion of all nutrients. The frequency of the phase III was lowest with FAT, followed by GLU and AA, in that order. The cycle of MMC was sustained and the phase III also appeared in the jejunum by infusion of NaCl. As the dose of NaCl solution was increased, the phase I was shortened and phase II was prolonged in the jejunum. PBF was significantly increased by the infusion of all nutrients. PBF infused with FAT significantly increased than those infused with GLU or AA. When NaCl solution was infused at 30 ml/h, PBF was not increased, whereas that was increased by the infusion at 75 ml/h. PBF was significantly increased in infusion with the 2.7% NaCl solution than those with the 0.9% or 1.8% solution, even in the infused rate was 75 ml/h. Changes in PBF by infusion of every nutrient and NaCl solutions were compared under the condition in which the osmotic ratios and the doses of the nutrients were the same as those of the NaCl solutions. There was no significant difference in PBF between AA and 2.7% NaCl solution infused at 75 ml/h. However, PBF with FAT infusion was significantly increased than that with 0.9% NaCl solution infused at 30 ml/h, and PBF with GLU infusion was significantly increased than that with the 1.8% NaCl solution infused at 75 ml/h. Gastrointestinal motility was changed by infusion of nutrients. At the same time, PBF was increased. Phase III suppression and changes in rate of cumulative spikes in the jejunum and the motility were thought to vary with chemical constituents of materials administrated, not with a difference in dose or osmotic ratio, and to reflect the increase in PBF