Body Clock – Astroglia Supporting Role Now Center Stage.

In Brain Circuitry, Brain Science by Brainy Days Ahead

Neurons in two small spheres in the brain (suprachiasmatic nuclei, or SCN) have had the starring role in studies of the body’s master clock. Now, the 6,000 astroglia (also called astrocytes) that are mixed in with the neurons are taking center stage. Astroglia are shaped like stars – their Latin name means starry glue.  So what has happened to elevate astroglia to their new starring role? First, scientists discovered that almost all of the body’s cells keep time, with a few exceptions like stem cells. Second, scientists began to understand the many talents and roles of astroglia, such as secreting and reabsorbing neurotransmitters and helping neurons form strengthened synapses to consolidate things we have learned. So what is their role in the SCN? Researchers at Washington University in St. Louis knew they would have to be able to manipulate the astroglia independently in living cells to discover what effect they were having in the SCN, and they successfully devised a toolkit that did just that. Using the toolkit, they ran two experiments, altering the astroglial clocks while monitoring the highly ritualized, daily behavior of wheel-running in mice. In both experiments, small changes to the astroglial clocks reliably slowed the mouse’s sense of time. Astroglia’s star is continuing to rise as researchers rush to shed light on their possible role in circadian rhythm, brain cancer, pre-term birth, manic depression and other diseases.