PREDICTION OF INDIVIDUAL VULNERABILITY TO STRESS-INDUCED GASTRIC ULCERATIONS IN RATS - A FACTOR-ANALYSIS OF SELECTED BEHAVIORAL AND BIOLOGICAL INDEXES

Fifty rats were subjected seriatim to 6 different test tasks (open-fie ld, startle, drug-induced stereotypy, oral finickiness, defensive bury ing, and memory for aversive event). This yielded 12 test-specific plu s 2 general biobehavioral measures (growth and defecation). These 14 m easures were subjected to factor analysis to determine if these measur es tapped a common construct of ''emotionality.'' The data yielded a 4 -factor structure of Finickiness, Defensiveness, Startle-Sensitivity, and Dopaminergic-Sensitivity that accounted for 62% of the variance. T hen, all rats were subjected to restraint-in-water stress to induce ga stric ulcerations. Multivariate techniques tested if there was a facto r or factor-structure that could predict individual differences in vul nerability to the stress-induced gastric ulcerations. Only the Dopamin ergic-Sensitivity factor predicted ulcerogenic vulnerability, and its predictive power resided substantially in the latency to initiate ster eotypic gnawing induced by apomorphine. This single test score correla ted with amount of ulcer (r = +0.52), accounting for 25% of the varian ce in ulcer, suggesting that 1. prescreening rats on this variable cou ld be a tool for reducing intrastrain experimental variance in future studies of treatments that modulate ulcerogenicity, and 2. the dopamin ergic system may be intimately involved in the causal path of ulceroge nicity. (C) 1997 Elsevier Science Inc.