EFFECT OF PYLOROPLASTY AND FUNDECTOMY ON THE DELAY OF GASTRIC-EMPTYING AND GASTROINTESTINAL TRANSIT OF LIQUID ELICITED BY ACUTE BLOOD-VOLUME EXPANSION IN AWAKE RATS

We evaluated the effects of fundectomy and pyloroplasty on the delay o f gastric emptying (GE) and gastrointestinal (GI) transit of liquid du e to blood volume (BV) expansion in awake rats. Male Wistar rats (N = 76, 180-250 g) were first submitted to fundectomy (N = 26), Heinecke-M ikulicz pyloroplasty (N = 25) or SHAM laparotomy (N = 25), After 6 day s, the left external jugular vein was cannulated and the animals were fasted for 24 h with water ad libitum. The test meal was administered intragastrically (1.5 ml of a phenol red solution, 0.5 mg/ml in 5% glu cose) to normovolemic control animals and to animals submitted to BV e xpansion (Ringer-bicarbonate, iv infusion, 1 ml/min, volume up to 5% b ody weight). BV expansion decreased CE and GI transit rates in SHAM la parotomized animals by 52 and 35.9% (P<0.05). Fundectomy increased GE and GI transit rates by 61.1 and 67.7% (P<0.05) and prevented the effe ct of expansion on GE but not on GI transit (13.9% reduction, P<0.05). Pyloroplasty also increased GE and GI transit rates by 33.9 and 44.8% (P<0.05) but did not prevent the effect of expansion on GF or GI tran sit (50.7 and 21.1% reduction, P<0.05). Subdiaphragmatic vagotomy bloc ked the effect of expansion on GE and GI transit in both SHAM laparoto mized animals and animals submitted to pyloroplasty. In conclusion 1) the proximal stomach is involved in the GE delay due to BV expansion b ut is not essential for the establishment of a delay in GI transit, wh ich suggests the activation of intestinal resistances, 2) pyloric modu lation was not apparent, and 3) vagal pathways are involved.