Biophysical effects of focused and defocused image stimuli on dopaminergic amacrine cell and AII amacrine cell in the mouse retina

Chung Him So, Ting Zhang, Qin Wang, Yan Yin Tse, Feng Pan

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review


Myopia is a substantial public health problem worldwide. Although it is known that defocused images alter eye growth and refraction, their effects on amacrine cells, especially dopaminergic ACs and AII ACs signaling that lead to either emmetropization or refractive errors, have remained elusive. This study aimed to determine if defocused images had an effect on the signaling of dopaminergic ACs and AII ACs in the mouse retina.

The GFP-labeled dopaminergic ACs and AII ACs were patched in adult EGR-1 and Fam 81a mice, respectively. A custom-made device was used to project defocused images onto the retina under a microscope. Mightex 1000 generated annulus and spots of varying sizes. Whole-cell recordings were conducted using electrodes with a resistance of 5-7 MΩ. After recording in the flat-mounted retinas, the patched cell was confirmed by injecting Neurobiotin. To study the impact of uncoupling AII ACs, Meclofenamic acid (MFA, 50μM), which inhibits gap junction conductance, was applied.

There were noticeable differences in the responses of dopaminergic ACs and uncoupled AII ACs to focused/defocused images. The excitatory postsynaptic currents (EPSCs) of coupled AII ACs displayed significant variations when exposed to spot and annulus stimuli. Surprisingly, coupled AII ACs did not exhibit significant differences in EPSCs when exposed to focused or defocused image stimuli. However, the application of a gap junction blocker (MFA, 50 μM) revealed significant divergence in EPSCs of uncoupled AII ACs between focused and defocused image stimuli.

It is hypothesized that AII ACs, particularly those with strong coupling, possess the ability to filter out the noise associated with defocused images. Uncoupled AII ACs are capable of detecting both focused and defocused images. Under the influence of focused and defocused image stimuli, such as myopic status, the biophysical properties of dopaminergic ACs can undergo changes that have the potential to impact dopamine release in the retina and contribute to the development of myopia.
Original languageEnglish
Title of host publicationInvestigative Ophthalmology & Visual Science
ISBN (Electronic)1552-5783
Publication statusPublished - 1 Jun 2024
EventARVO Annual Meeting 2024 - Seattle, United States
Duration: 5 May 20249 May 2024


ConferenceARVO Annual Meeting 2024
Country/TerritoryUnited States


  • retina


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