May 2003
Volume 44, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2003
Synaptic Organization of GABAergic Amacrine Cells in the Salamander Retina
Author Affiliations & Notes
  • J. Zhang
    Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, United States
  • C.Y. Yang
    Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, United States
  • Footnotes
    Commercial Relationships  J. Zhang, None; C.Y. Yang, None.
  • Footnotes
    Support  NIH Grant RO1 EY10322
Investigative Ophthalmology & Visual Science May 2003, Vol.44, 5176. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      J. Zhang, C.Y. Yang; Synaptic Organization of GABAergic Amacrine Cells in the Salamander Retina . Invest. Ophthalmol. Vis. Sci. 2003;44(13):5176.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Abstract: : Purpose: GABA is a major inhibitory neurotransmitter in amacrine cells of the vertebrate retina. Physiological studies have demonstrated that GABAergic amacrine cells in the salamander retina participate in feedback inhibition to bipolar cells and feedforward inhibition to ganglion cells and other amacrine cells. However, little is known about the synaptic organization of GABAergic amacrine cells in this species. This study focused on the types and distribution of GABA-immunoreactive (GABA-IR) amacrine synapses in the IPL. Methods: Photomontages of electron micrographs covering 3618 µm2 of the IPL were obtained by using a post-embedding GABA immunogold method. Results: 1) GABA-IR amacrine synapses (N=459) were distributed throughout the IPL, with a peak at the proximal margin of sublamina a and a somewhat higher concentration in sublamina b. 2) The majority of output targets (81%) were not GABA-IR. 3) Most of the contacts (94%) were simple synapses with one postsynaptic element identified as a process of an amacrine cell (50%), bipolar cell (19%) or ganglion cell (25%); 2.6% were serial synapses and 3.4% were unidentified. 4) Of the 86 postsynaptic bipolar terminals, 63% participated in a reciprocal feedback synapse with the same presynaptic GABA-IR amacrine profile. 5) There appeared to be no preference between amacrine contacts with rod- or cone- dominant bipolar cells (9.1% vs 8.9%) or in the total number of amacrine synapses in sublaminas a and b (52% vs 47%). Conclusion: GABA-IR amacrine cells in salamander preferentially contact other amacrine cells, indicating that they are more involved in lateral inhibitory pathways. This is in contrast to mammals (cat, monkey), in which about 50% of the GABAergic amacrine output is onto bipolar cells and thereby they are more likely to exert their effects directly on the through pathway.

Keywords: retina: proximal(bipolar, amacrine, and gangli • neurotransmitters/neurotransmitter systems • immunohistochemistry 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×