Gastric blood flow following simultaneous administration of serotonin and histamine

Left gastric-artery flow was measured with a Medicon FM-6 gated sine-wave electromagnetic flowmeter. Histamine, 4 µg./min., produces a small increase (9%) in flow. Serotonin in increasing doses of 10, 20, 40, and 60 µg./kg./min. given concomitantly with the same dose of histamine, progressively augment left gastric-artery flow in increments of 25, 43, 87, and 189%, respectively. The increases in left gastric-artery flow found with increasing doses of serotonin represent a single, direct, exponential relationship.