Adenosine and Dopamine Receptors Coregulate Photoreceptor Coupling via Gap Junction Phosphorylation in Mouse Retina

Adenosine and dopamine may coregulate photoreceptor coupling through opposing effects on the PKA pathway and Cx36 phosphorylation.

• Gap junctions in retinal photoreceptors help reduce voltage noise and integrate rod signals during mesopic vision.
• Dopamine, acting through D4 receptors, may uncouple photoreceptors by inhibiting adenylyl cyclase and reducing PKA activity.
• Adenosine levels increase in darkness and could serve as a signal to regulate photoreceptor coupling by affecting gap junction phosphorylation.
• Pharmacological activation of A2a receptors or inhibition of D4 receptors in light-adapted retinas enhanced photoreceptor coupling.
• In dark-adapted retinas, inhibiting A2a receptors or activating D4 receptors decreased Cx36 phosphorylation, indicating a PKA-dependent mechanism.
• A2a-deficient retinas displayed impaired regulation of photoreceptor gap junction phosphorylation and altered expression of D4 receptor and adenylyl cyclase mRNAs.

AI simplified