Journal of Biosciences

, Volume 26, Issue 2, pp 179–191

Differential expression of syntaxin-1 and synaptophysin in the developing and adult human retina

Article

DOI: 10.1007/BF02703642

Cite this article as:
Nag, T.C. & Wadhwa, S. J Biosci (2001) 26: 179. doi:10.1007/BF02703642

Abstract

Synaptophysin and syntaxin-1 are membrane proteins that associate with synaptic vesicles and presynaptic active zones at nerve endings, respectively. The former is known to be a good marker of synaptogenesis; this aspect, however, is not clear with syntaxin-1. In this study, the expression of both proteins was examined in the developing human retina and compared with their distribution in postnatal to adult retinas, by immunohistochemistry. In the inner plexiform layer, both were expressed simultaneously at 11–12 weeks of gestation, when synaptogenesis reportedly begins in the central retina. In the outer plexiform layer, however, the immunoreactivities were prominent by 16 weeks of gestation. Their expression in both plexiform layers followed a centre-to-periphery gradient. The immunoreactivities for both proteins were found in the immature photoreceptor, amacrine and ganglion cells; however, synaptophysin was differentially localized in bipolar cells and their axons, and syntaxin was present in some horizontal cells. In postnatal-to-adult retinas, synaptophysin immunoreactivity was prominent in photoreceptor terminals lying in the outer plexiform layer; on the contrary, syntaxin-1 was present in a thin immunoreactive band in this layer. In the inner plexiform layer, however, both were homogeneously distributed. Our study suggests that (i) syntaxin-1 appears in parallel with synapse formation; (ii) synaptogenesis in the human retina might follow a centre-to-periphery gradient; (iii) syntaxin-1 is likely to be absent from ribbon synapses of the outer plexiform layer, but may occur at presynaptic terminals of photoreceptor and horizontal cells, as is apparent from its localization in these cells, which is hitherto unreported for any vertebrate retina.

Key words

Developmenthuman retinaimmunohistochemistrysynaptogenesissynaptophysinsyntaxin-1

Abbreviations used

DPX

Dibutylpthala polystyrene xylene

IPL

inner plexiform layer

PBS

phosphate buffer saline

PD

postnatal day

OPL

outer plexiform layer

Copyright information

© Indian Academy of Sciences 2001

Authors and Affiliations

  1. 1.Department of AnatomyAll India Institute of Medical SciencesNew DelhiIndia