title: Neurochemical properties of enkephalinergic neurons in lumbar spinal dorsal horn revealed by preproenkephalin-green fluorescent protein transgenic mice.
abstract: Enkephalin (ENK) has been implicated in nociceptive transmission in the spinal cord while its functional role is not clear because of difficulties in ideally visualizing ENKergic neurons. We thus developed preproenkephalin-green fluorescent protein transgenic mice to better identify ENKergic neurons. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) together with immunohistochemistry and in situ hybridization were first employed to confirm the successful transgenic manipulation and its application in showing spinal ENKergic neurons. The proportions of ENKergic neurons in the spinal cord laminae I, II, III and IV-VI among dorsal horn neurons were 15.8 +/- 3.1%, 39.5 +/- 3.3%, 11.8 +/- 1.9% and 10.7 +/- 2.1%, respectively. Double labeling with other molecules was then performed to further clarify the neurochemical properties of spinal ENKergic neurons. GABA was found to exist in 42.9 +/- 2.8% of ENKergic neurons that were mainly located in lamina I-III. The proportions of parvalbumin-, calretinin-, calbindin- and neuronal nitric oxide synthase-positive cells among the ENKergic neurons were 5.2 +/- 0.7%, 42.6 +/- 2.3%, 25.8 +/- 2.2% and 11.1 +/- 1.6%, respectively. Compared with previously findings obtained with ENK antibody labeling, this line of newly generated mice can be a reliable tool for the study of specific spinal ENKergic neuronal population.
authors.affiliation: Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, Fourth Military Medical University, Xi'an, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Huang
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Wen
authors.initials: W
authors.lastname: Wang
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Koshimizu
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Wei
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kaneko
authors.forename: Yun-Qing
authors.initials: YQ
authors.lastname: Li
authors.forename: Sheng-Xi
authors.initials: SX
authors.lastname: Wu
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism; D002452:Cell Count / Q000379:methods; D004745:Enkephalins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000235:genetics; D008161:Lumbosacral Region; D051379:Mice; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009448:Neurochemistry / Q000379:methods*; D020671:Posterior Horn Cells / Q000378:metabolism*; D011498:Protein Precursors / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D004745:Enkephalins; D009419:Nerve Tissue Proteins; D011498:Protein Precursors; D012333:RNA, Messenger; D049452:Green Fluorescent Proteins; D005680:gamma-Aminobutyric Acid; C033660:preproenkephalin