SUMMARYBlood flow in the left gastric artery was measured with an electromagnetic flowmeter in nine conscious beagle dogs. In the fasting state gastric motility and secretion exhibited periodical changes with an average cycle interval of 115-4+9-7 min. During a quiescent period, when gastric motility and secretion were minimal, the mean blood flow was stable at 33 9 + 3-8 ml/min. During the contracting phase each peristaltic contraction was coupled with a rapid fall and rise in blood flow (from 10 5 + 1 9 ml/min below to 212 + 3 8 ml/min above the precontraction levels) in 20-30 s. In addition there was a sustained elevation in blood flow (58 6 + 6-4 ml/min at the peak) lasting for 29-1 + 2-8 min. The onset of sustained blood flow elevation was preceded by that of motility in 63 % of the cycles. In 23 % of the cycles blood flow started to rise before the contracting phase began. Pepsin peaks coincided with blood flow peaks in two dogs and preceded the latter in the others. Feeding abolished periodic increases in motility and blood flow. It is concluded that left gastric arterial blood flow is not steady but exhibits dynamic changes in phase with periodic motor and secretory activities of the stomach in fasting conscious dogs.

Effects of acute portal hypertension on systemic hemodynamics after hepatectomy were evaluated by portal venous stenosis (PVS) model in dogs. In protocol 1, portal hypertension of about twice portal venous pressure (PVP) decreased cardiac output (CO) and left atrial pressure (LAP) by 24.5% (p < 0.01) and 1.0 mm Hg (p < 0.01), respectively. In protocol 2, stepwise PVS demonstrated that CO change (%) and LAP change (mm Hg) were inversely proportional to PVP change (r = -0.937 and -0.883, respectively). The ratio of CO change to LAP change with stepwise PVS was comparable to that obtained by repeated hemorrhage in protocol 3. The present study shows that low CO with portal hypertension is caused by a reduction of venous return to the heart.