Compartmental localization of gamma-aminobutyric acid type B receptors in the cholinergic circuitry of the rabbit retina

C L Zucker, J E Nilson, Berndt Ehinger, N M Grzywacz

Research output: Contribution to journalArticlepeer-review

16 Citations (SciVal)

Abstract

Although many effects of gamma-aminobutyric acid (GABA) on retinal function have been attributed to GABA(A) and GABA(C) receptors, specific retinal functions have also been shown to be mediated by GABA(B) receptors, including facilitation of light-evoked acetylcholine release from the rabbit retina (Neal and Cunningham [1995] J. Physiol. 482:363-372). To explain the results of a rich set of experiments, Neal and Cunningham proposed a model for this facilitation. In this model, GABA(B) receptor-mediated inhibition of glycinergic cells would reduce their own inhibition of cholinergic cells. In turn, muscarinic input from the latter to the glycinergic cells would complete a negative-feedback circuitry. In this study, we have used immunohistochemical techniques to test elements of this model. We report that glycinergic amacrine cells are GABA(B) receptor negative. In contrast, our data reveal the localization of GABA(B) receptors on cholinergic/GABAergic starburst amacrine cells. High-resolution localization of GABA(B) receptors on starburst amacrine cells shows that they are discretely localized to a limited population of its varicosities, the majority of likely synaptic-release sites being devoid of detectable levels of GABA(B) receptors. Finally, we identify a glycinergic cell that is a potential muscarinic receptor-bearing target of GABA(B)-modulated acetylcholine release. This target is the DAPI-3 cell. We propose, based on these data, a modification of the Neal and Cunningham model in which GABA(B) receptors are on starburst, not glycinergic amacrine cells.
Original languageEnglish
Pages (from-to)448-459
JournalJournal of Comparative Neurology
Volume493
Issue number3
DOIs
Publication statusPublished - 2005

Subject classification (UKÄ)

  • Neurology

Keywords

  • directional selectivity
  • receptor
  • muscarinic
  • ganglion cell
  • amacrine cell
  • acetylcholine
  • glycine
  • receptor targeting

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