Antinociception elicited by exogenous EM-1, EM-2, and β-endorphin (END) in inflamed paws. Left, Dose-dependent antinociceptive effects at 5 min after intraplantar injections (p < 0.001, ANOVA, linear regression). Middle, Time course of EM-1- and EM-2-induced antinociception. *p < 0.001, Bonferroni’s test. Right, Lack of EM-1- and EM-2-induced antinociception after systemic (subcutaneous) injection at the neck (p > 0.05, two-way repeated-measures ANOVA). Data are expressed as means ± SEM.