Intersublaminar vascular plexus: the correlation of retinal blood vessels with functional sublaminae of the inner plexiform layer.

PURPOSE: Interactions between vasculature and neurons provide important insight into the function of the nervous system, as well as into neurological diseases wherein these interactions are disrupted. This study characterizes a previously unreported retinal vascular plexus and examines potential sites of neurovascular interaction. METHODS: Vascular, neuronal, and glial elements were visualized using immunohistochemical markers. The distribution of vascular layers was measured and compared across eccentricities. Intensity profiles were calculated from confocal image reconstructions to reveal the proximity of vasculature to neuronal and glial processes. RESULTS: Retinal vasculature forms a plexus that coincides with the dendritic processes of OFF cholinergic amacrine cells within the inner plexiform layer. Across eccentricities, this plexus comprises approximately 8% of the total length of horizontally running blood vessels in the retina. Processes of Müller glia and OFF cholinergic amacrine cells colocalize with the blood vessels that form the intersublaminar plexus. CONCLUSIONS: In the retina, vasculature lacks autonomic control, but shows efficient local regulation. Although the source of this regulation is unclear, these results suggest that cholinergic amacrine cells and Müller glia may interact with the intersublaminar plexus to influence vasomotor activity. This may indicate a key role in modulating reciprocal interactions between neuronal activity and blood flow.