Behavioral responses of adult male F344 and WKY in the OFT, basally (NS) and immediately after one hour restraint stress (S) without and with repeated testing (RT). (A) Time spent in center (seconds) was significantly increased by stress (S) in WKYs and reversed by repeated stress and test (S+RT); (B) inner line crossing; (C) latency to leave the center is significantly increased by stress in WKYs, and the effect is reversed by repeated testing; (D) number of total crossing was decreased by stress in both strains; (E) the number of rears differed significantly by strains in the NS group, and stress decreased number of rears significantly in F344; (F) time (seconds) spent grooming. Values are means +/- SEM. Asterisks indicate significant effect of strain; pound signs indicate significant effect of repeated testing; plus signs indicate significant effect of stress. All significant values are p < 0.05 by Bonferroni post hoc test.