Figure 1

Opioid-induced hyperalgesia in 23 strains of inbred mice. For each strain, mice were tested for mechanical nociceptive thresholds at baseline and after 4 days of morphine treatment. Nociceptive thresholds after morphine treatment were divided by baseline values to obtain the fraction of baseline values. For each strain n = 8 mice. Mean values are displayed +/- S.E.M.