Abstract
The effects of Mr2096, Mr2097, diprenorphine, (-)bremazocine and Mr2266 on jumping latencies were evaluated in Swiss, CXBK, C57BL, CXBH and CBA strains of mice. Mr2096 and Mr2097 respectively produced analgesia and hyperalgesia in these strains of mice. Thus their effects on nociception were mediated by stereoselective opioid receptors. Diprenorphine also produced hyperalgesia which might be mediated by both mu and kappa receptors. Kappa receptors also appeared to mediate hyperalgesia at least in Swiss and CBA strains, as both (-)bremazocine and Mr2266 shortened the jumping latencies.
