Glia Excitation in the CNS Modulates Intact Behaviors and Sensory-CNS-Motor Circuitry

Glial cells play a role in many important processes, though the mechanisms through which they affect neighboring cells are not fully known. Insights may be gained by selectively activating glial cell populations in intact organisms utilizing the activatable channel proteins channel rhodopsin (ChR2XXL) and TRPA1. Here, the impacts of the glial-specific expression of these channels were examined in both larval and adult Drosophila. The Glia > ChR2XXL adults and larvae became immobile when exposed to blue light and TRPA1-expressed Drosophila upon heat exposure. The chloride pump expression in glia > eNpHR animals showed no observable differences in adults or larvae. In the in situ neural circuit activity of larvae in the Glia > ChR2XXL, the evoked activity first became more intense with concurrent light exposure, and then the activity was silenced and slowly picked back up after light was turned off. This decrease in motor nerve activity was also noted in the intact behaviors for Glia > ChR2XXL and Glia > TRPA1 larvae. As a proof of concept, this study demonstrated that activation of the glia can produce excessive neural activity and it appears with increased excitation of the glia and depressed motor neuron activity.