Identification of cholinoceptive glycinergic neurons in the mammalian retina

Academic Article

Abstract

  • The light-evoked release of acetylcholine (ACh) affects the responses of many retinal ganglion cells, in part via nicotinic acetylcholine receptors (nAChRs). nAChRs that contain β2α3 neuronal nicotinic acetylcholine receptors have been identified and localized in the rabbit retina; these nAChRs are recognized by the monoclonal antibody mAb210. We have examined the expression of β2α3 nAChRs by glycinergic amacrine cells in the rabbit retina and have identified different subpopulations of nicotinic cholinoceptive glycinergic cells using double and triple immunohistochemistry with quantitative analysis. Here we demonstrate that about 70% of the cholinoceptive amacrine cells in rabbit retina are glycinergic cells. At least three nonoverlapping subpopulations of mAb210 glycine-immunoreactive cells can be distinguished with antibodies against calretinin, calbindin, and γ-aminobutyric acid (GABA)A receptors. The cholinergic cells in rabbit retina are thought to synapse only on other cholinergic cells and ganglion cells. Thus, the expression of β2α3 nAChRs on diverse populations of glycinergic cells is puzzling. To explore this finding, the subcellular localization of β2α3 was studied at the electron microscopic level. mAb210 immunoreactivity was localized on the dendrites of amacrines and ganglion cells throughout the inner plexiform layer, and much of the labeling was not associated with recognizable synapses. Thus, our findings indicate that ACh in the mammalian retina may modulate glycinergic circuits via extrasynaptic β2α3 nAChRs. © 2002 Wiley-Liss, Inc.
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    Digital Object Identifier (doi)

    Author List

  • Dmitrieva NA; Pow DV; Lindstrom JM; Keyser KT
  • Start Page

  • 167
  • End Page

  • 175
  • Volume

  • 456
  • Issue

  • 2