title: Neurokinin A and neurokinin B in the human retina.
abstract: Very recently, the authors found levels of neurokinin (NK) A-like immunoreactivities in the human retina which were more than five times higher than those of substance P (SP). The present study aimed to find out how many of these immunoreactivities can be attributed to NKA and NKB and then the exact distribution pattern of both NKA and NKB was evaluated in the human retina and compared with that of SP. For this purpose, NKA-like immunoreactivities were characterized in the human retina by reversed phase HPLC followed by radioimmunoassay using the K12 antibody which recognizes both NKA and NKB. Furthermore, the retinae from both a 22- and 70-year-old donor were processed for double-immunofluorescence NKA/SP and NKB/SP. The results showed that NKA contributes to approximately two thirds and NKB to approximately one third of the immunoreactivities measured with the K12 antibody. NKA was found to be localized in sparse amacrine cells in the proximal inner nuclear layer, in displaced amacrine cells in the ganglion cell layer with processes ramifying in stratum 3 of the inner plexiform layer and also in sparse ganglion cells. By contrast, staining for NKB was only observed in ganglion cells and in the nerve fiber layer. Double-immunofluorescence revealed cellular colocalization of NKA with SP and also of NKB with SP. Thus, the levels of NKA and NKB are more than three and two times higher than those of SP, respectively. Whereas the distribution pattern of NKA is typical for neuropeptides, the localization of NKB exclusively in ganglion cells is atypical and unique.
authors.affiliation: Department of Ophthalmology, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Eduard
authors.initials: E
authors.lastname: Schmid
authors.forename: Johannes
authors.initials: J
authors.lastname: Leierer
authors.forename: Gerhard
authors.initials: G
authors.lastname: Kieselbach
authors.forename: Barbara
authors.initials: B
authors.lastname: Teuchner
authors.forename: Martina
authors.initials: M
authors.lastname: Kralinger
authors.forename: Reiner
authors.initials: R
authors.lastname: Fischer-Colbrie
authors.forename: James E
authors.initials: JE
authors.lastname: Krause
authors.forename: Quynh Anh
authors.initials: QA
authors.lastname: Nguyen
authors.forename: Gertrud
authors.initials: G
authors.lastname: Haas
authors.forename: Katrin
authors.initials: K
authors.lastname: Stemberger
authors.forename: Josef
authors.initials: J
authors.lastname: Troger
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005455:Fluorescent Antibody Technique; D006801:Humans; D015288:Neurokinin A / Q000378:metabolism*; D015287:Neurokinin B / Q000378:metabolism*; D011863:Radioimmunoassay; D012160:Retina / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism
chemical_list: D013373:Substance P; D015288:Neurokinin A; D015287:Neurokinin B