has soma location has soma location expresses expresses sensory neuron of dorsal root ganglion sacral dorsal root ganglion substance P neuron 2026-03-13T11:13:54Z A peptidergic nociceptor whose soma is located in the sacral dorsal root ganglion and that expresses substance P, an 11-amino-acid neuropeptide cleaved from protachykinin-1 (encoded by TAC1). This small-diameter neuron frequently co-expresses CGRP and belongs to the TrkA-positive peptidergic population. Upon nociceptive activation, it releases substance P both centrally in the spinal cord dorsal horn and peripherally at sensory nerve terminals, mediating neurogenic inflammation through NK1 receptor signalling (Haberberger et al. 2019, PMID:31293388). Substance P-immunoreactive neurons have been consistently identified in human DRG by immunohistochemistry across multiple studies. SP neuron sacral dorsal root ganglion SP neuron protachykinin-1 sacral dorsal root ganglion