Glymphatic System

Glial cells

Most abundant cells in the central nervous system; originally thought to be purely non-functional "glue" for neurons

Glial cells function

Perform a variety of functions including neuronal insulation, communication between neurons, nutrient transport, and waste transport

Astrocytes function

Contribute to the formation of the blood-brain barrier; physically and metabolically support and communicate with neurons; regulate the formation and functions of synapses; maintain water homeostasis and the microenvironment in the brain

Astrocyte image

Oligodendrocyte function

Produces myelin sheathes to ensure to saltatory action potential propagation along the axons.

Oligodendrocyte image

Microglia function

Responsible for the elimination of microbes, dead cells, redundant synapses, protein aggregates, and other particulate and soluble antigens that may endanger the CNS; mediators of neuroinflammation and can induce or modulate a broad spectrum of cellular responses

Microglia image

Aquaporins (AQPs) description

Diverse family of membrane proteins that are expressed predominantly in tissues in which edema and fluid imbalances are of major concern

Aquaporins (AQPs) function

Responsible for the bi-directional passage of water and small solutes across the cell membranes while preserving ion gradients

Aquaporins image

Aquaporin-4 (AQP4) description

A water-selective transporter expressed mainly by astrocytes in small processes in the proximity of the subarachnoid area, ventricular spaces, and blood vessels

Aquaporin-4 (AQP4) function

Necessary not only for water homeostasis but also to clear small molecules and metabolites, including Ab and Tau proteins, from interstitial space

What triggers AQP activity?

Interneuron release of peptides

Vasoactive intestinal peptide (VIP) description

A neuropeptide that functions as a neuromodulator and neurotransmitter

Vasoactive intestinal peptide (VIP) function

Involved in several cellular processes that are relevant to glymphatic clearance and is thought to be released during high-frequency stimulation

What frequency stimulation causes neurons to release peptides that increase glymphatic clearance of amyloid?

40Hz