Fig. 4. Effects of gabapentin and other α²δ subunit ligands on 25 mM KCl-evoked γ-amino butyric acid (GABA) release in synaptosomes prepared from the locus coeruleus (LC) and its adjacent tissues. Data are presented as percentage change from baseline release. Synaptosomes from normal (A ) and spinal nerve ligated (SNL: B ) rats were treated with buffer, gabapentin (GBP, 1–100 μM), pregabalin (PGB, 100 μM), L-isoleucine (L-ILe, 10 μM), or D-isoleucine (D-ILe, 10 μM). N = 5–10. *P < 0.05 versus  buffer.