Figure 5.

α₂-adrenergic receptor antagonist yohimbine reduces the analgesic effect of taltirelin on mechanical nociception. Yohimbine HCl (yoh) was administered either i.p. ((a); 0.1, 0.3 and 1 mg kg⁻¹) or i.t. ((b); 1 and 3 μg) 15 min before the administration of taltirelin hydrate (tal, 1 mg kg⁻¹, s.c. in (a) and 0.3 μg, i.c.v. in (b), administered at time zero). Each point represents the mean (±s.e.m.) result from six mice. Ordinates: mean normalized tail flick latencies (tail flick test; left) and nociceptive thresholds (tail pressure test; right). Abscissae: time in minutes after taltirelin application. The asterisks indicate data points for which a significant difference between the taltirelin-only and yohimbine-treated groups was observed, as determined by two-tailed non-parametric Bonferroni-type multiple comparisons following the Kruskal–Wallis test (three comparisons in four groups in (a), and two comparisons in three groups in (b), ^*P<0.05).