Abstract
Purpose:
The link between vasculature and neurons becomes the key component in understanding of retinal neurovascular diseases. The aim of this study was to determine whether the position of neuronal components relative to retinal vasculature within the adult inner mouse retina is related to physiology.
Methods:
Light responses of the ganglion cells (GCs) were recorded in mouse retinal whole mounts with loose patch-clamp technique. Retinal blood vessels were visualized in living tissue with sulforhodamine. The physiological On-, Off, and On-Off responses of the ganglion cells were correlated with the stratification level of their dendrites in the inner plexiform layer (IPL) relatively to the blood vessels. Blood vessels in the fixed tissue were visualized with isolectin or secondary anti mouse antibodies. The position of the blood vessels was standardized relative to established borders in the retina labeled with the antibody to choline acethyl transferase and other cellular markers. High resolution confocal image stacks were taken.
Results:
After electrophysiological recordings retinal blood vessels can be reliably visualized in living and fixed tissue. Three major layers of blood vessels were localized in the ganglion cell layer, outer plexiform layer, and between the IPL and inner nuclear layer. The fourth sparse layer was found in the Off-sublamina of the IPL, co-stratified with the Off-cholinergic band. All ganglion cells stratified adjacent or distal to the fourth layer exhibited Off-light responses and were classified as Off-GCs. The cells stratified proximal to that layer were On-GCs.
Conclusions:
We demonstrated the presence of the fourth layer of the vasculature within the mouse IPL. Importantly, this newly revealed vascular layer is placed near the border of major functional strata IPL separating On and Off sublaminas, two major parallel channels of the retina, implicating its key role in modulating retinal activity. In living retinal whole mount the blood vessels can serve as landmark to confirm stratification of the cells and their physiological type.
Keywords: 531 ganglion cells •
436 blood supply •
691 retina: proximal (bipolar, amacrine, and ganglion cells)