Animals have specific ways of escaping external danger. And a collaborative study now reveals that there are signals promoted by molecules released by neurons to make fruit fly larvae (Drosophila melanogaster) escape harmful external stimuli.
Alisson Gontijo, principal investigator of the Integrative Biomedicine laboratory at CEDOC-NMS, was part of this collaborative effort between several institutions that included the University of Bonn, Hamburg and Duke, among other research centers. “We characterized the neuronal circuit that mediates the detection of light in neurons to the component of the central nervous system circuit that distinguishes light from other dangerous stimuli: touch,” says Alisson.
“We showed that Dp7 hub neurons differentially respond to each stimulus, and this difference consists in the selective secretion of different neuropeptides: sNPF or the insulin-like peptide 7 (Ilp7), for the response to touch or to light, respectively” he continues. "Both Ilp7 and Lgr4, a G protein-coupled receptor, are transmitted in a light-aversion response and we present consistent data and biochemical data on the interaction of the two."
Uncovering these complex neuronal circuits is a great victory to which other equally important discoveries are added. In this study, led by Peter Soba of the Limes Institute in Bonn, Alisson's group - which included Ednilson Varela and Fabiana Herédia - was particularly involved in what the researcher calls the “deorphanization” of the Lgr4 receptor. This receptor is similar to human receptors that recognize relaxin, a peptide neuromodulator with an insulin-like structure: “Relaxin signaling pathways are highly conserved in evolution and have been implicated in many human diseases, including neuropsychiatric ones such as depression and anxiety. This study adds to the knowledge that invertebrate relaxins are involved in controlling innate behavior, suggesting that Drosophila is a much more valuable model than previously thought for understanding the role of this signaling pathway and related human diseases.”
The study was published in the journal Current Biology under the title "A neuropeptidergic circuit blocks the selective behavior of Drosophila larvae" is available here.