Pentobarbital may protect against neurogenic inflammation after surgery via inhibition of substance P release from peripheral nerves of rats

•Neurogenic inflammation originates from local release of inflammatory mediators, such as substance P (SP), by primary afferent neurons after noxious stimuli like surgery.•Cultured dorsal root ganglion (DRG) neurons have both central and peripheral branches.•Pentobarbital significantly inhibited capsaicin-induced, but not high K+-induced, SP release from rat DRG cells.•However, a high concentration of ketamine did not block SP release.•Thus, the inhibitory effects of pentobarbital on SP release from peripheral terminals may protect against neurogenic inflammation after surgery.