Effect of pyridoxine on mice gastric ulcers and brain catecholamines after an immobilization stress.

Fifty adult female Swiss albino mice were injected with either 1.11 mg/kg body weight pyridoxine or saline, subsequently they were all submitted to an immobilization stress with a complete fast for 17 h. At the end of this period, the animals were sacrificed, the gastric mucosa was dissected for ulcer count, and brain noradrenaline, dopamine and serotonin were determined by liquid chromatography. In addition, 26 nonstressed mice were used as controls, 16 of them being fed at libitum and 10 submitted to the same fasting period as the first two groups. In the stressed animals, the average number of gastric ulcers per mouse was twice as large in the saline-treated group than in the pyridoxine-treated group (p < 0.05). With a single exception, no ulcer was found in the non stressed controls. Brain norepinephrine content was almost identical in fasting controls and in stressed mice treated with pyridoxine; in the stressed animals treated with saline, the average norepinephrine content was higher by 15% and in the fed controls lower by 11% than in the two preceding groups. Pyridoxine treatment entailed a very significant reduction (p < 0.002) of norepinephrine variability, mainly due to the absence of high values (> or = 750 ng/g of fresh brain) which occurred only in the saline-treated group. Similar results were yielded for brain dopamine. No variations were observed for brain serotonin. These results suggest the antistress effect of pyridoxine.