Factors in the etiology of restraint erosions in parabiotic rats

Rats joined in surgical parabiosis for 25 to 30 days were tested by restraining one member of the pair on a movable cart while allowing the second member to remain free to move about. These rats were compared with other rats joined in pseudoparabiosis for 25 to 30 days so that the behavioral aspects of parabiosis were reproduced but blood sharing did not occur. Pseudoparabiotic rats were also tested on the movable cart at the end of the recovery and adaptation period. Gastric erosions formed in the unrestrained members of both the parabiotic and pseudoparabiotic pairs with an incidence and severity that did not differ statistically. The experimental results fail to support the hypothesis that humoral factor(s) are critical in restraint ulcer pathogenesis in the rat.