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Updated: Aug 14, 2026
Immunohistochemical and Calcium Imaging Methods in Wholemount Rat Retina
Published on: October 13, 2014
Prenatal development of calbindin D-28K and parvalbumin immunoreactivities in the human retina
1John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City 84132, USA. xyan@uci.edu
Insights
Calbindin D-28K (CB) and parvalbumin (PV) are expressed early in human fetal retina development, appearing in various cell types by 24 weeks. Their expression patterns suggest roles in neuronal maturation and foveal development.
Area of Science:
- Neuroscience
- Developmental Biology
- Ophthalmology
Background:
- Calcium-binding proteins calbindin D-28K (CB) and parvalbumin (PV) are crucial for neuronal function.
- Understanding their expression patterns during human retinal development is vital for insights into neuronal maturation and visual system formation.
Purpose of the Study:
- To investigate the spatiotemporal expression of CB and PV in the developing human retina from 13 weeks gestation to term.
- To correlate the expression of these proteins with cellular differentiation and potential roles in retinal development, including foveal formation.
Main Methods:
- Immunocytochemistry was employed to detect CB and PV immunoreactivity in human fetal retinas.
- Retinas from fetuses aged 13 weeks to term were analyzed.
Main Results:
- Both CB and PV were detectable by 13 weeks gestation, with widespread expression across retinal layers by 24 weeks.
- PV was found in ganglion cells, horizontal cells, and some amacrine cells; CB was present in amacrine cells, horizontal cells, ganglion cells, and distinctly in bipolar cells by 24 weeks.
- CB expression was observed in foveal cones by 24 weeks, intensifying by 32 weeks, and also noted in photoreceptors beyond the fovea near term. Enhanced CB expression was seen nasally in the optic nerve head between 13-24 weeks.
Conclusions:
- CB and PV expression in retinal neurons appears to parallel their differentiation, suggesting a role in neuronal maturation.
- Early expression of PV and CB in ganglion cell axons may support optic nerve outgrowth and guidance.
- CB's presence in developing foveal cones indicates a potential involvement in foveal formation during the perinatal period.
Abstract:
Two calcium binding proteins, calbindin D-28K (CB) and parvalbumin (PV),immunoreactivities were examined by immunocytochemistry in the retinas of human fetuses aged from 13 weeks (W) of gestation to term. CB- and PV-immunoreactive products were both detectable at 13 W and appeared in all layers in a roughly inside-out order by 24 W. PV-immunostaining occurred in virtually all ganglion cells, most horizontal cells, and a few amacrine cells. CB-immunoreactivity was found in most amacrine cells and some horizontal cells, and a subset of cells in the ganglion cell layer that were more frequent in the nasal than the temporal retina at 13-15 W. Bipolar cells were distinctly immunostained for CB by 24 W. Foveal cones showed faint CB labeling by 24 W and intense staining at 32 W. The patterns of CB- and PV-immunoreactivities by birth were similar to those at 32 W with the addition of faint CB-immunolabeling occurring beyond the fovea in the photoreceptors. A stronger expression of CB was seen in the nasal side of the optic nerve head from 13-24 W, peaking at 15 W. The results indicate that CB and PV expression in ganglion cells and inner nuclear layer neurons proceeds in parallel with their somal and process differentiation, suggesting a possible role for these proteins in neuronal maturation. The early expression of PV and CB in ganglion cell axons might be related to optic nerve outgrowth, including path-finding at the optic chiasm. CB expression in cones and other cells in the fovea may indicate that it is involved in foveal formation that occurs during the perinatal period.
