Persistent inflammatory nociception increases levels of dynorphin 1-17 in the spinal cord, but not in supraspinal nuclei involved in pain modulation.
Parra MC, Nguyen TN, Hurley RW, Hammond DL. Persistent inflammatory nociception increases levels of dynorphin 1-17 in the spinal cord, but not in supraspinal nuclei involved in pain modulation. J Pain. 2002 Aug; 3(4):330-6.