Abstract
Presentation Description :
Capillaries throughout the brain are wrapped by pericytes and astrocytes, and together they form the blood brain barrier. Neurovascular coupling (i.e. changes in blood flow in response to neural activity) relies, in part, on interactions between neurons and the BBB elements, often through astrocytes. Retinal processing in mice and primates is supported by a trilaminar vessel network which helps to replenish the energy associated with biological computation. Interestingly, astrocytes are restricted to only one of the vascular layers, and very little is known about the elements of the BBB in the other 2 (deeper) layers. Here I will present 3D morphological reconstructions of retinal capillaries and the surrounding elements. We find that Müller glia, a type of radial glia, extend processes to the capillaries and together form a near complete coverage of the pericyte-laden vessels. The extent of this ensheathment is similar to astrocytic ensheathment of capillaries found in the hippocampus. Puffs of extracellular ATP evoked dynamic calcium signals in the sheaths, indicating that they are functional signaling units that also express purinergic receptors. This arrangement likely means that neurotransmitters released by neurons do not have direct access to the pericytes and vessel walls, and instead must use Müller glia as a signaling intermediate.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.