Glial cells in the brain are generally considered to be electrically inert, simply providing a support system for excitable neurons. But at least one class of glial cell can fire action potentials, scientists showed this year.
Ragnhildur Káradóttir, now at the University of Cambridge, UK, and her colleagues reported that about half of NG2-expressing glia in the rat brain receive input from synapses. The cells also show currents when stimulated by the neurotransmitter glutamate.
The excitable NG2 glia were much more vulnerable to oxygen starvation, which promotes glutamate release, than were non-excitable glia. Such oxygen starvation occurs in stroke, cerebral palsy and spinal-cord injury.