New study documents role of glial cells in brain

GCaMP6s expression
Expression of protein calcium sensors in astrocytes and traces of 10 individual astrocytes from an intact larva.

Glial cells, once considered passive bystanders of neural transmission, are now understood to provide support and protection for neurons in the central and peripheral nervous systems. Astrocytes, the most abundant glial cells in the brain, closely associate with neuronal synapses and perform supporting roles in neuronal activity by providing oxygen and sugars and by removing carbon dioxide. New research findings demonstrate a function scientists have proposed but not proven—that astrocytes not only support but actively participate in processing information in the brain.

A team of scientists led by Marc Freeman, Ph.D., director of the Vollum Institute, documented in fruit flies a newly understood pathway for transmitting signals within the brain. The research, published in the journal Nature, provided the first in vivo demonstration of astrocyte calcium signaling as essential for behaviors such as olfactory or startle responses.

The team demonstrated that neurons release neurotransmitters that bind astrocytes and change astrocyte calcium signaling, which then regulates downstream neurons. These findings make possible opportunities for the development of new, targeted therapies for regulating a wide range of neurological functions in humans, from hunger to mood.

The scientists will next investigate the extent of this type of signaling in the brain, as well as the influence of astrocytes on neuromodulators such as dopamine or serotonin.

Freeman authored the study while a professor and vice chair of the Department of Neurobiology at the University of Massachusetts Medical School and investigator in the Howard Hughes Medical Institute. Co-authors include Zhiguo Ma and Tobias Stork of the Howard Hughes Medical Institute and Dwight E. Bergles of Johns Hopkins University School of Medicine.

The work was supported NINDS grant R01 NS053538.

Read the full OHSU news release.