title: Altered synaptophysin expression in the rat spinal cord after chronic constriction injury of sciatic nerve.
abstract: Injury to the peripheral nervous system can lead to spontaneous pain, hyperalgesia and allodynia. Previous studies have shown sprouting of Abeta-fibres into lamina II of the spinal cord dorsal horn after nerve injury and the formation of new synapses by these sprouts. Synaptophysin is a presynaptic vesicle protein, useful in the identification of synaptogenesis. Here we investigated whether synaptogenesis as measured by the expression of synaptophysin protein correlates with symptoms of neuropathic pain in rats with a chronic constriction injury (CCI) of the sciatic nerve. We used immunohistochemistry, Western immunoblotting and densitometry to study the distribution of synaptophysin and to quantify relative protein. Synaptophysin was increased in the ipsilateral dorsal horn with a peak level on day 14 and returned to baseline on day 21 post-CCI. Synaptophysin levels temporally correlated with thermal hyperalgesia but not with tactile allodynia. Our results indicate that thermal hyperalgesia in CCI significantly correlates with synaptogenesis within the superficial layers of the dorsal horn.
authors.affiliation: Anesthesiology Research Laboratory, Chang-Gung Memorial Hospital, 123 Ta- Pei Road, Niao Shung Hsiang, Kaohsiung Hsien, 833, Taiwan.
authors.forename: An-Kuo
authors.initials: AK
authors.lastname: Chou
authors.forename: Rania
authors.initials: R
authors.lastname: Muhammad
authors.forename: Shu-Min
authors.initials: SM
authors.lastname: Huang
authors.forename: Jing-Tsang
authors.initials: JT
authors.lastname: Chen
authors.forename: Chao-Liang
authors.initials: CL
authors.lastname: Wu
authors.forename: Chung-Ren
authors.initials: CR
authors.lastname: Lin
authors.forename: Tsung-Hsing
authors.initials: TH
authors.lastname: Lee
authors.forename: Sheng-Han
authors.initials: SH
authors.lastname: Lin
authors.forename: Cheng-Yan
authors.initials: CY
authors.lastname: Lu
authors.forename: Lin-Cheng
authors.initials: LC
authors.lastname: Yang
mesh_terms: D000818:Animals; D034961:Antigens, Nuclear / Q000378:metabolism; D015153:Blotting, Western / Q000379:methods; D007839:Functional Laterality / Q000502:physiology; D007150:Immunohistochemistry / Q000379:methods; D008026:Ligation; D008297:Male; D009474:Neurons / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000293:injuries*; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism*; D016708:Synaptophysin / Q000378:metabolism*; D013697:Thermosensing / Q000502:physiology; D013997:Time Factors
chemical_list: D034961:Antigens, Nuclear; D016708:Synaptophysin