Differential expression of synaptoporin and synaptophysin in primary sensory neurons and up-regulation of synaptoporin after peripheral nerve injury.
Synaptoporin and synaptophysin are integral membrane components of synaptic vesicles. The distribution of synaptoporin and its relationship with synaptophysin in sensory afferent fibers remain unclear. In the present study, we showed that in the rat dorsal root ganglia synaptoporin was expressed in subsets of small neurons that contain either calcitonin gene-related peptide or isolectin B4, and was distributed in their afferent terminals in laminae I-II of the spinal cord. 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. However, 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. After peripheral nerve injury, synaptoporin expression was up-regulated in small dorsal root ganglion neurons, and synaptoporin level was increased in their afferent terminals. Thus, synaptoporin and synaptophysin have topographically distinct distributions in afferent fibers. Synaptoporin is a major synaptic vesicle protein in Adelta- and C-fibers in both physiological and neuropathic pain states.
Sun
T
T
Institute of Neuroscience, Key Laboratory of Neurobiology, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China.
Xiao
H-S
HS
Zhou
P-B
PB
Lu
Y-J
YJ
Bao
L
L
Zhang
X
X
D000704:Analysis of Variance; D000818:Animals; D019771:Axotomy / Q000379:methods; D015153:Blotting, Western / Q000379:methods; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D002452:Cell Count / Q000379:methods; D007839:Functional Laterality / Q000502:physiology; D005727:Ganglia, Spinal / Q000473:pathology; D005786:Gene Expression Regulation / Q000502:physiology*; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D037102:Lectins / Q000378:metabolism; D008297:Male; D009475:Neurons, Afferent / Q000378:metabolism*; D010523:Peripheral Nervous System Diseases / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D016708:Synaptophysin / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors
D037102:Lectins; D012333:RNA, Messenger; D016708:Synaptophysin; C504262:Synpr protein, rat; D015740:Calcitonin Gene-Related Peptide