Figure 6From: PK20, a new opioid-neurotensin hybrid peptide that exhibits central and peripheral antinociceptive effects Time-course of the antinociceptive effect of intravenously administered PK20 (4 mg/kg) vs. intraperitoneally injected morphine (4 mg/kg). Each column represents the mean value ± SEM of 6 - 8 animals. *p < 0.05; **p < 0.001, significantly different from morphine-injected animals.Back to article page