Neuropeptides and Somatosensory Systems

Primary sensory neurons have their cell bodies in dorsal root ganglia and have axons which convey somatosensory and visceral information from the body to neuronal pathways in the spinal cord and brainstem. Glutamate is the main neurotransmitter used by dorsal root ganglion (DRG) cells, but many also utilize neuropeptides, which are released centrally to function as neurotransmitters but can also be released peripherally, where they function as neurohumoral factors, regulating blood flow and the tissue response to injury. This article will briefly review the organization and subtypes of DRG cells, their regulation by growth factors, the changes that take place after nerve injury and inflammation, and the functional role of primary sensory neuropeptides.