Fig. 2.

Neural pathways underlying the memory enhancing effects of OEA in the inhibitory avoidance task. (A) Performance (mean ± SEM) in the 48-hour retention test of Sprague-Dawley rats given post-training systemic injections of OEA (5 mg·kg⁻¹, i.p.) and intracerebral injection of phosphate-buffered saline (PBS, 0.5 μl) or lidocaine (2%, 0.5 μl) into the nucleus tractus solitarii (NTS). (B) Expression of c-fos mRNA in the NTS of rats given systemic injections of OEA (10 mg·kg⁻¹, i.p.); arrow indicates NTS location; bar, 100 mm (C) Performance of rats given post-training systemic injections of OEA (5 mg·kg⁻¹, i.p.) and intracerebral injection of saline (0.2 μl) or propranolol (0.5 μg in 0.2 μl) into the basolateral complex of the amygdala (BLA). Kruskal-Wallis ANOVA showed a significant effect (A) H₃ = 19.049, P = 0.0003, n = 10–11 and (C) H₃ = 13.866, P = 0.031, n = 10–12, for NTS and BLA, respectively. **, P < 0.01 compared with corresponding control group. Diagrams on the right show rat brain coronal sections (24) demonstrating injection sites randomly selected among rats included in the final analysis (● vehicle; ■ OEA).