['We previously showed that subsequent intrathecal (i.t.) injection of resveratrol (30\xa0μg) significantly reverses morphine-evoked neuroinflammation in morphine-tolerant rats. The present study examined the underlying mechanism.', 'Male Wistar rats were implanted with two i.t. catheters, one of which was connected to a miniosmotic pump and used for morphine (15\xa0μg/h) or saline infusion for 120 hours. To examine the effects on spinal cord expression of histone deacetylase 1 (HDAC1), the inflammatory cytokine tumor necrosis factor-α (TNF-α), and TNF receptor (TNFR) 1 and TNFR2 during tolerance induction, a tail-flick test was performed prior to infusion and after 24 hours, 48 hours, 72 hours, 96 hours, and 120 hours of infusion.', 'Resveratrol treatment prior to morphine challenge restored the antinociceptive effect of morphine in morphine-tolerant rats and reversed the morphine infusion-induced increase in HDAC1, TNF-α, and TNFR1 expression. Moreover, chronic morphine infusion increased TNFR1-specific expression in neuron in morphine-tolerant rat spinal cords, and this effect was almost completely inhibited by resveratrol treatment prior to morphine challenge.'] Does resveratrol reverse morphine-induced neuroinflammation in morphine-tolerant rats by reversal HDAC1 expression?