"Glia are enlisted into the conversation that neurons are having, and they may modulate that by releasing these factors that control activity," Littleton says. "Elevated calcium may create a situation where the glia are no longer releasing these factors in a regulated way, but they're releasing them all the time."
In the human brain, astrocytes are the cells most similar to the fruit fly glial cells observed in this study, according to the researchers. These cells envelop the cell bodies of neurons and are also the most abundant type of glial cell in the human brain. It is not yet known whether these cells express one of the five human versions of the zydeco gene.
Although further study is needed, the findings suggest that preventing calcium from building up in glial cells or astrocytes could reduce neuronal excitability and decrease the tendency to seize in response to environmental stimuli, according to the researchers. "It's still a long way off, but the fly work suggests that reducing glial calcium levels would be effective in toning down excitability," Littleton says.
The MIT researchers are now looking for other components of the pathway that connects glial calcium levels to neuronal hyperactivity, which could lead to the discovery of other potential drug targets.
|Contact: Sarah McDonnell|
Massachusetts Institute of Technology