Corticotropin releasing factor-like immunoreactivity (CRF-LI) in horizontal cells of the developing rat retina.
This study describes a phenomenon of transient expression of corticotropin releasing factor-like immunoreactivity (CRF-LI) in immature horizontal cells of the developing rat retina. These cells could be distinguished from those destined to become CRF-LI amacrine cells in the adult by their location within the outer portion of the neuroblastic layer (NBL) and by their ontogenetic pattern. Upon initial detection on postnatal day 3 (PD-3), faint CRF-LI cellular profiles were found in the outer portion of the NBL, limited to the central region of the retina. Subsequently, on PD-5, these profiles began to appear in the periphery, forming a single horizontal row along the outermost aspect of the developing inner nuclear layer (INL), concomitant with the establishment of the outer plexiform layer (OPL). The results of our birth-dating study combining immunohistochemistry and [3H]-thymidine autoradiography indicated that these cells were generated between embryonic day 14 and 18. These findings are consistent with them being horizontal cells. Between PD-7 and PD-9, CRF-LI in horizontal cells began to diminish progressively following a center-to-periphery gradient such that only sporadic, faintly immunoreactive patches of cells could be seen by the time of eye opening (PD-15). Around PD-19, it declined to levels below immunohistochemical detection. However, when rats were reared in complete darkness beginning at birth until PD-21, the period of CRF-LI expression in horizontal cells was prolonged and persisted throughout the first three postnatal weeks of development.
Zhang
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Department of Neurobiology and Anatomy, University of Rochester, NY.
Yeh
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D000818:Animals; D001345:Autoradiography; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism*; D003623:Dark Adaptation; D005260:Female; D007124:Immunoenzyme Techniques; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism*
D003346:Corticotropin-Releasing Hormone