Postprandial gastric blood flow in conscious dogs.

Left gastric arterial blood flow was measured with an electromagnetic flowmeter in conscious dogs. Immediately after the ingestion of 300 g of meat or milk, gastric blood flow increased to 250-270% of the control but declined to preprandial levels in 10 min despite the presence of milk in the stomach. Gastric distension with a 300-ml balloon evoked a response of approximately 50% of that of milk, but continuous distension failed to maintain gastric hyperemia. The initial peak response to milk and distension was reduced by hexamethonium (-58 and -62%, respectively) and oxethazaine (-43 and -29%, respectively) but not by phenoxybenzamine, propranolol, or atropine. Thus the initial response was induced by both the contact of food with the mucosa and the distension of the stomach partly via the activation of neural reflexes. Gastric blood flow after the peak was dependent on the type of food and its route of administration; it was elevated by 30% after a meat meal, remained close to fasting levels after oral administration of milk, and fell below fasting levels (-17%) after intragastric administration of milk. An intraduodenal infusion of milk, but not water, reduced gastric blood flow below the control (-26%). Pentagastrin, which caused approximately 50% of the maximal acid secretion, increased gastric blood flow by only 10%.