Nociceptive integration: Does it have a peripheral component?

The spinal cord dorsal horn is generally regarded as the first site where modulation and integration of nociceptive input occur. It is rare that nociceptive terminals and axons are given any greater role than being transducers and conduits. It is our hypothesis that this view of peripheral nociceptors is oversimplified and that peripheral sensory processing rivals the complexity of central spinal cord processing. The complexity of peripheral organization is supported by (1) the presence of a variety of peripheral receptors and ligands, (2) the probability that differential transport of receptors occurs with dorsal root ganglion cells, and (3) evidence that nociceptive input can be modified and integrated in the periphery before being transmitted centrally. It is hoped that unraveling the complexities of peripheral sensory processing will lead to new insights for pain therapy.