Fig. 15.

Average nociceptive scores of unilateral Ce-treated rats in Experiment 5. Rating scale nociceptive scores are shown in A and flinch nociceptive scores are shown inB. Error bars indicate SEM. In this experiment, Ce-treated rats received systemic morphine and intraplantar formalin on two separate occasions. On one occasion, formalin was delivered to the hindpaw ipsilateral to the unilateral Ce treatment (muscimol or saline), and on the other occasion formalin was delivered to the contralateral hindpaw. Note the similar pattern of results obtained with the rating scale and flinch-frequency methods of nociceptive scoring. There were no significant differences in nociceptive scores under morphine between either group of unilateral Ce sham lesion rats and unilateral Ce lesion rats treated withcontralateral formalin. In unilateral Ce lesion rats treated with ipsilateral formalin, however, morphine sulfate (4 mg/kg, s.c.) produced significantly less antinociception compared with allother groups. B, *p < 0.05; **p < 0.01, Mann–Whitney Utest, compared with both groups of unilateral Ce sham lesion rats treated with systemic morphine; ^Xp < 0.05;^XXp < 0.01, Wilcoxon signed-rank test, compared with unilateral Ce lesion rats treated with systemic morphine plus contralateral formalin.