Our work on the biogenic amine octopamine influencing the initiation and maintenance of flight in the fruit fly Drosophila melanogaster was accepted by the Journal of Neuroscience last week. This study is a collaboration between Carsten Duch and me just before Carsten joined ASU. We both supervised undergraduate student Frauke Christansen (co-first author of the study, now in Würzburg) who did most of the experiments in the lab of Hans-Joachim Pflüger here in Berlin.
The title of the study is "Flight initiation and maintenance deficits in flies with genetically altered biogenic amine levels". It shows that in contrast to what was believed for about 20 years, octopamine is not required for flight initiation nor maintenance. Instead, we uncovered antagonistic interplay between octopamine and its synthesis precurser tyramine. This study was done using flies mutant for the enzyme (tyramine beta hydroxylase) catalyzing the synthesis of octopamine from tyramine. These flies lack octopamine completely and sport 8-fold increased tyramine levels. Reducing the action of tyramine alone by feeding tyramine receptor blockers to these flies is sufficient to restore flight performance to the otherwise severely impaired mutants. However, also restoring octopamine alone rescues the mutant defect. Further experiments suggest that octopamine and tyramine exert their antagonistic effects probably at different locations in the fly's nervous system.
This study was important for my own research as octopamine is regarded as the main transmitter mediating reward and I study learning in flying flies (it means I can't use these mutants in my learning paradigm , at least not without restricting the mutation only to certain neurons - work in progress). Another point worth noting is the interesting parallel of the main transmitter of reward in flies (octopamine) controlling behavior, just as the main mediator of reward in humans (dopamine) also controls behavior (as evidenced in Parkinson's patients lacking dopaminergic neurons).
Personally for me, this publication comes at a crucial time when I'm actively on the hunt for a faculty position. A paper in this journal is significant, because of its impact factor (IF) of about 7.5 (Explanation of IF).
An entertaining side note to this is that at least one of my evaluators at the DFG did not spot the obvious connection of this work to my research focus and suggested I dropped this project...