METOCLOPRAMIDE INHIBITS DEVELOPMENT OF ESOPHAGEAL-VARICES IN RAT MODEL

We examined the preventive effect of metoclopramide on the development of esophageal varices in a rat model. Thirty rats were divided into t hree groups: metoclopramide (7.5 mg/kg twice a day, intraperitoneally) , control group I (saline 2 ml/kg twice a day, intraperitoneally), and control group II (incised lower esophageal sphincter and metocloprami de 7.5 mg/kg twice a day, intraperitoneally). On the 14th postoperativ e day, lower esophageal sphincter pressure in the metoclopramide group (8.6 +/- 1.4 cm H2O) increased more than in the control groups (5.4 /- 0.5, 5.0 +/- 0.5 cm H2O, P < 0.01). Development of small collateral vessels from the spleen to the retroperitoneum was evident only in th e metoclopramide group, as seen on the portography (P < 0.01). Histolo gically, the variceal area of the horizontal cross section of the esop hagus in the metoclopramide group (0.62 +/- 0.26 mm(2)) was significan tly smaller than in the controls (2.67 +/- 0.95, 2.78 + 0.82 mm(2)), d etermined using an image processor-analyzer for photographing histolog ical specimens (P < 0.01). We also investigated the effect of metoclop ramide on smooth muscle cells in the rat portal vein, using isometric- tension recording. Metoclopramide relaxed the smooth muscle precontrac ted with norepinephrine, in a concentration-dependent manner. Thus, me toclopramide inhibits the development of esophageal varices in this ra t model due to both an increase in resistance of the lower esophagus a nd to development of small collaterals.