DIFFERENCES IN THE STRESS-RESPONSE OF WISTAR-KYOTO (WKY) RATS FROM DIFFERENT VENDORS

Wistar-Kyoto (WKY) rats are hyperresponsive to stress and prone to str ess ulcer. However, some variability in these general findings has bee n reported. This variability may reflect differences in the rat stock from different WKY rat vendors. WKY rats from Taconic (WKY-T), Harlan Sprague-Dawley (WKY-H), and Charles River (WKY-CR) were observed in th e open-field test (OFT) and the forced-swim test (FST), and subsequent ly exposed to ulcerogenic water-restraint stress. There were no differ ences between vendor stocks in the FST, but WKY-CR rats were significa ntly more immobile in the OFT as compared to WKY-T and a Wistar contro l group. WKY-CR and WKY-H rats revealed significantly more ulcers as c ompared to WKY-T and Wistar rats. The WKY inbreeding programs at Charl es River and Harlan, as compared to the outbreeding practice at Taconi c may contribute to these vendor differences. These data indicate that WKY rat sublines from different vendors represent an important source of variability when comparing studies of stress reactivity using WKY rats. (C) 1997 Elsevier Science Inc.