Synaptoporin (SYNPR)

Synaptophysin was expressed in 57% of synaptoporin-containing small dorsal root ganglion neurons and in large dorsal root ganglion neurons. In the spinal dorsal horn, synaptophysin-immunolabeling was weak in the afferent fibers in lamina I, outer lamina II and the dorsal part of inner lamina II, but strong in the afferent fibers in laminae III-IV. a subpopulation of isolectin B4-positive small dorsal root ganglion neurons expressed both synaptoporin and synaptophysin, and their afferent fibers were mainly distributed in the ventral part of inner lamina II. synaptoporin expression was up-regulated in small dorsal root ganglion neurons, and synaptoporin level was increased in their afferent terminals. Synaptoporin is a major synaptic vesicle protein in Adelta- and C-fibers in both physiological and neuropathic pain states.