The Effect of Optogenetically Activating Glia on Neuronal Function

Glia, or glial cells, are considered a vital component of the nervous system, serving as an electrical insulator and a protective barrier from the interstitial (extracellular) media. Certain glial cells (i.e., astrocytes, microglia, and oligodendrocytes) within the CNS have been shown to directly affect neural functions, but these properties are challenging to study due to the difficulty involved with selectively-activating specific glia. To overcome this hurdle, we selectively expressed light-sensitive ion channels (i.e., channel rhodopsin, ChR2-XXL) in glia of larvae and adult Drosophila melanogaster. Upon activation of ChR2, both adults and larvae showed a rapid contracture of body wall muscles with the animal remaining in contracture even after the light was turned off. During ChR2-XXL activation, electrophysiological recordings of evoked excitatory junction potentials within body wall muscles of the larvae confirmed a train of motor nerve activity. Additionally, when segmental nerves were transected from the CNS and exposed to light, there were no noted differences in quantal or evoked responses. This suggests that there is not enough expression of ChR2-XXL to influence the segmental axons to detect in our paradigm. Activation of the glia within the CNS is sufficient to excite the motor neurons

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 \u3e ChR2XXL adults and larvae became immobile when exposed to blue light and TRPA1-expressed Drosophila upon heat exposure. The chloride pump expression in glia \u3e eNpHR animals showed no observable differences in adults or larvae. In the in situ neural circuit activity of larvae in the Glia \u3e 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 \u3e ChR2XXL and Glia \u3e 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

The Effect of Optogenetically Activating Glia on Neuronal Function

Glia, or glial cells, are considered a vital component of the nervous system, serving as an electrical insulator and a protective barrier from the interstitial (extracellular) media. Certain glial cells (i.e., astrocytes, microglia, and oligodendrocytes) within the CNS have been shown to directly affect neural functions, but these properties are challenging to study due to the difficulty involved with selectively-activating specific glia. To overcome this hurdle, we selectively expressed light-sensitive ion channels (i.e., channel rhodopsin, ChR2-XXL) in glia of larvae and adult Drosophila melanogaster. Upon activation of ChR2, both adults and larvae showed a rapid contracture of body wall muscles with the animal remaining in contracture even after the light was turned off. During ChR2-XXL activation, electrophysiological recordings of evoked excitatory junction potentials within body wall muscles of the larvae confirmed a train of motor nerve activity. Additionally, when segmental nerves were transected from the CNS and exposed to light, there were no noted differences in quantal or evoked responses. This suggests that there is not enough expression of ChR2-XXL to influence the segmental axons to detect in our paradigm. Activation of the glia within the CNS is sufficient to excite the motor neurons

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 \u3e ChR2XXL adults and larvae became immobile when exposed to blue light and TRPA1-expressed Drosophila upon heat exposure. The chloride pump expression in glia \u3e eNpHR animals showed no observable differences in adults or larvae. In the in situ neural circuit activity of larvae in the Glia \u3e 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 \u3e ChR2XXL and Glia \u3e 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

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