title: Postnatal development of NK1, NK2, and NK3 neurokinin receptors expression in the rat retina.
abstract: The biological effects of tachykinins are mediated by three distinct receptors, the neurokinin 1 receptor (NK1-R), NK2-R, and NK3-R. There is no information available concerning the development of these receptors in the retina. In the present study, we investigated the localization of tachykinin receptors, using antisera directed against NK1-R, NK2-R, and NK3-R in the adult and developing rat retinas. Numerous NK1-R immunoreactive (NK1-R IR) cells were already observed in the proximal part of the neuroblastic layer in the retina at postnatal day 5 (P5). The distribution and intensity of NK1-R IR cells and processes in the inner nuclear layer (INL) and inner plexiform layer (IPL) at P10 were similar to those of adult retina. Most NK1-R IR cells located in the proximal part of INL, which were morphologically amacrine cells. In the contrast to the early expression of NK1-R IR cells, no NK3-R IR structures existed in the neuronal elements of the retina until P10. NK3-R IR processes were first detected in the outer plexiform layer (OPL) at P10. At P15, NK3-R IR somata were slightly stained in the distal and middle parts of the INL, and NK3-R IR processes were present in the OPL and the upper part of the IPL. During P15-P30, the number of NK3-R IR somata located in the INL remarkably increased. These NK3-R IR cells were morphologically bipolar and amacrine cells. This study provides differential cellular distribution of NK1-R IR cells and NK3-R IR cells in the INL of the rat retina. Our findings suggest that NK1-R and NK3-R are involved in different visual circuits and retinal maturation, and NK3-R may play previously unknown important roles in the visual processes of the rat.
authors.affiliation: Department of Nursing, Osaka City University, Asahi-cho, Abenoku, Osaka, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Oyamada
authors.forename: K
authors.initials: K
authors.lastname: Takatsuji
authors.forename: E
authors.initials: E
authors.lastname: Senba
authors.forename: P W
authors.initials: PW
authors.lastname: Mantyh
authors.forename: M
authors.initials: M
authors.lastname: Tohyama
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D002454:Cell Differentiation; D048429:Cell Size; D018507:Gene Expression Regulation, Developmental; D007106:Immune Sera; D007150:Immunohistochemistry; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D018040:Receptors, Neurokinin-1 / Q000378:metabolism; D018041:Receptors, Neurokinin-2 / Q000378:metabolism; D018042:Receptors, Neurokinin-3 / Q000378:metabolism; D018039:Receptors, Tachykinin / Q000378:metabolism*; D012160:Retina / Q000033:anatomy & histology / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism; D014795:Visual Pathways / Q000166:cytology / Q000254:growth & development / Q000378:metabolism
chemical_list: D007106:Immune Sera; D018040:Receptors, Neurokinin-1; D018041:Receptors, Neurokinin-2; D018042:Receptors, Neurokinin-3; D018039:Receptors, Tachykinin; D013373:Substance P