Adenosine signaling in glia modulates metabolic state-dependent behavior in Drosophila.
1 Institute for Physiology II - University of Bonn
An animal’s metabolic state strongly influences its behavior. Hungry animals must engage in food seeking and feeding behaviors in order to restore their energy balance. Activity of the neuronal networks underlying these behaviors themselves consume energy. Indeed, neuronal excitability and synaptic transmission are among the most energy expensive processes in an animal’s body. Yet neurons do not uptake glucose -their main energy source- from the circulating blood and can neither store it. This highly conserved function is rather carried out by glial cells. In addition to their role as energy suppliers of the nervous system, glia can sense and modulate neurotransmission and animal behavior based on more recent work in various invertebrate and vertebrate models. In this present study, we show that the metabolic state of hungry Drosophila melanogaster can be transmitted to glial cells by adenosine. Adenosine signaling in glia modulates their intracellular calcium activity which leads to modification of neural activity and ultimately of food foraging and feeding behaviors. Interestingly, adenosine signaling in specific glial subpopulations has different, in some cases opposite, effects on their activity and on fly behavior. Taken together, we provide a new mechanism that glial cells can use to sense the metabolic state of the animal and modulate its behavior accordingly.