Increased pain perception and attenuated opioid antinociception in paradoxical sleep-deprived rats are associated with reduced tyrosine hydroxylase staining in the periaqueductal gray matter and are reversed by L-DOPA

► 96 hours of PSD increased the pain sensitivity to a noxious thermal stimulus (46 °C). ► PSD-induced thermal hyperalgesia is reversed by L-DOPA and L-DOPA plus morphine. ► The number of cell bodies immunopositive for TH in the PAG is reduced in rats after PSD.