Neural Garbage Collectors

What am I looking at?

This is an image of an adult zebrafish brain. The network of red lines outlining the shape of the brain (1) represents the densely packed blood vessels that span the exterior of the brain. The small green dots scattered throughout these vessels are fluorescent granular perithelial cells (2).

Biology in the background

The brain, like any other organ, has a metabolic system that allows it to function properly. The blood vessels around the exterior of this zebrafish brain bring essential nutrients to the brain cells, providing them with the resources they need. However, this process also produces waste, which can be toxic to cells if it accumulates. Some of this waste is carried away by the cerebrospinal fluid. However, a relatively little-known class of cells called fluorescent granular perithelial cells (or FGPs) are now thought to aid in this waste removal process.

FPGs are thought to be key in establishing the blood-brain barrier that separates brain tissue from the bloodstream, protecting the brain from many compounds in the blood that might be dangerous. In addition, this specific type of granular perithelial cell is thought to act as a “trash collector” for the brain, picking up waste produced by brain cells and storing it for disposal.

This zebrafish brain is about 3 millimeters long (or roughly eight times smaller than a human thumbnail), 2 millimeters thick (or roughly 10 times smaller than a human thumbnail), and 2.5 millimeters wide (or roughly nine times smaller than a human thumbnail).

Technique  

This image was created using confocal microscopy.