“…Carrageenaninduced peripheral inflammation upregulates preproN/OFQ mRNA, N/OFQ peptide, and NOP binding in primary sensory neurones of dorsal root ganglia (Andoh, Itoh, & Kuraishi, 1997;Itoh et al, 2001), and dorsal horn (Fu, Wang, Wang, Yu, & Wu, 2007;Fu, Zhu, Wang, & Wu, 2007) in addition to the hypothalamus (Rosén, Lundeberg, Bytner, & Nylander, 2000) revealing plasticity in the N/OFQ system. Pain patients have elevated serum N/OFQ that is augmented in patients with long-lasting chronic pain (Ko, Kim, Woo, & Kim, 2002), although females with fibromyalgia syndrome have lower plasma N/OFQ (Anderberg, Liu, Berglund, & Nyberg, 1998) suggesting that a correlation between pain and serum N/OFQ may depend on factors such as the presence of inflammation, gonadal steroids, and stress.…”