[Effect of substance P on gastric secretion and serum gastrin levels]

I. m. administration of substance P (5, 10, 15 and 20 micrograms/kg) insignificantly increased gastric secretion induced with histamine. I. v. administration of substance P (2 and 5 micrograms/kg/hr) considerably potentiated gastric secretion induced with histamine. Microapplication of substance P to the hypothalamus (10 micrograms in 3 microliters of saline) also led to a considerable increase of the gastric secretory response, whereas the same microapplication to the amygdala decreased gastric secretion induced with histamine. Microapplication of substance P and an alpha-adrenoblocking agent to these cerebral structures augmented the response of the stomach secretory cells. The level of the serum gastrin decreased following i. v. administration of substance P to hungry dogs.