Vagus nerves and the gastric tissue histamine concentration in pylorus ligated albino rats.

Gastric tissue histamine concentration was determined, 6 and 16 hours after pylorus ligation in vagus intact and vagotomized albino rats and the results were compared with those of respective control animals, sacrificed, 6 and 16 hours after ether anaesthesia alone. The gastric tissue histamine concentration of rats subjected to none of the experimental situations was also determined and taken into comparison. The results show that the stress of pylorus ligation reduced the gastric tissue histamine concentration, the reduction being more with increased duration of stress. On the other hand, subdiaphragmatic vagtomy preserved the histamine concentration of gastric tissue irrespective of the duration to which the animals were exposed following pylorus ligation. It appears that increase in vagal discharges during stress leads to increased liberation of histamine from the gastric wall, thereby, reducing the gastric tissue histamine concentration; the reduction being proportional to the duration of stress and increase in vagal discharges, whereas, in the absence of vagal impulses following subdiaphragmatic vagotomy, the gastric tissue histamine concentration is preserved in spite of the stress to which the animals were exposed.