Dopamine D1 and D4 receptors contribute to light adaptation in ON-sustained retinal ganglion cells.
Level 5 - mechanism / opinion, no new human data
Preclinical ex vivo animal physiological study without human clinical data.
PubMed 34817291 · doi:10.1152/jn.00218.2021
What was done
Researchers performed single-cell retinal patch-clamp electrophysiological recordings in ex vivo mouse retina preparations to determine how activating dopamine D1 receptors (D1Rs) and D4 receptors (D4Rs) alters light-evoked and spontaneous excitatory inputs to ON-sustained (ON-s) ganglion cells.
What was found
Activating either D1Rs or D4Rs decreased light-evoked excitatory inputs to ON-s ganglion cells, with the sum of their peak response reductions matching the effect of light adaptation to a rod-saturating background. Agonists for both receptors primarily decreased the frequency of spontaneous excitatory events, indicating an upstream site of action. No exact numerical data, sample sizes, or p-values were reported in the abstract.
Why it matters
This paper identifies how distinct dopamine receptor subtypes in outer and inner retinal layers cooperatively decrease ganglion cell sensitivity during light adaptation to help the retina function across wide dynamic ranges of illumination.
Limits
The study is confined to an ex vivo mouse model and a single subtype of retinal ganglion cell, which may not capture full in vivo human physiology. The abstract provides no sample sizes (n of animals or recorded cells), specific drug concentrations, or quantitative effect sizes.
Cited by
- supports Dopamine is expressed in the eye and modulates retinal neuron activity to adapt vision across different luminance conditions.