Potentiation of cold swim stress analgesia in rats by diazepam

It was hypothesized that diazepam (DZP) would attenuate the analgesia produced by cold swim stress because of its anxiolytic and biochemical anti-stress properties. In fact, it had the opposite effect. Administered alone, neither DZP nor its vehicle affected the nociceptive thresholds of rats, as assessed by a flinch-jump test. In combination with cold swim stress, DZP elevated nociceptive thresholds significantly more than did the stressor alone. This was true whether DZP was injected before or after exposure to the stressor, or whether or not DZP administration was acute or chronic.