title: Correlation between the distribution of SP and CGRP immunopositive neurons in dorsal root ganglia and the afferent sensation of preputial frenulum.
abstract: The aim of this study was to explore the distribution of substance P (SP) and calcitonin gene-related peptide (CGRP) immunoreactive nerve terminals in the penis prepuce and the preputial frenulum. The possible correlation between SP- and CGRP-immunopositive neurons in dorsal root ganglia (DRG) and the afferent sensation of the penile preputial frenulum is also discussed. Immunohistochemistry showed SP- and CGRP-positive nerve terminals in the epidermal basal layer of the prepuce and frenulum in adult human males. The majority of the nerve terminals presented as bundles of different lengths and a few as enlarged nodosities. The density of SP- and CGRP-immunopositive nerve terminals in the preputial frenulum was significantly higher than those in the penis prepuce (P<0.01). Fluoro-Gold (FG) retrograde tracing method was used to trace the origin of nerve terminals in Sprague-Dawley rats. SP and CGRP immunofluorescence labeling was employed to detect the distribution of SP- and CGRP-immunoreactive neurons in DRG. FG retro-labeled neurons were localized in L(6) -DRG and S(1) -DRG. All the FG/SP and FG/CGRP double-labeled neurons were medium or small-sized. One-third of the FG-labeled neurons were SP-immunoreactive, and a half of them CGRP-immunoreactive in L(6) -DRG and S(1) -DRG, respectively. The FG/SP/CGRP-labeled neurons accounted for one fifth of the FG retro-labeled neurons. Taken together, these data suggest that the SP- and CGRP-immunopositive nerve fibers may participate in the transmission of afferent sensation in the preputial frenulum.
authors.affiliation: Department of Anatomy, School of Medicine of Zhejiang University, Hangzhou, China.
authors.forename: Zhong-Min
authors.initials: ZM
authors.lastname: Wu
authors.forename: Yong-Feng
authors.initials: YF
authors.lastname: Chen
authors.forename: Peng-Nian
authors.initials: PN
authors.lastname: Qiu
authors.forename: Shu-Cai
authors.initials: SC
authors.lastname: Ling
mesh_terms: D000328:Adult; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D008297:Male; D009412:Nerve Fibers / Q000378:metabolism; D009475:Neurons, Afferent / Q000166:cytology / Q000378:metabolism*; D010413:Penis / Q000294:innervation*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012677:Sensation / Q000502:physiology*; D013373:Substance P / Q000378:metabolism*; D055815:Young Adult
chemical_list: D013373:Substance P; D015740:Calcitonin Gene-Related Peptide