This week we profile a recent publication in eLife from the laboratory of
Dr. Michael Gordon (pictured, top row 3rd from right) at UBC.
Can you provide a brief overview of your lab’s current research focus?
My lab is focused on understanding how the brain encodes sensory information and behavior. We study this problem in the fruit fly because it has a wealth of tools to manipulate and measure neuron function, accessible behaviors, and a quick generation time that allows us to perform lots of experiments. The specific questions we are studying revolve around how the brain processes information about taste, and how specific populations of neurons in the brain contribute to controlling feeding. We believe that a deeper understanding of the fly brain will lead to fundamental insight into the function of other animals’ brains (like ours).
What is the significance of the findings in this publication?
Salt has long been an enigma in the taste field, because it elicits different responses depending on concentration. We love a little bit of salt (French fries, etc.) but really don’t like it at high concentrations (think about swallowing sea water). It has been proposed that this dual effect arises from activation of two taste cell types – a ‘low salt’ cell that produces attraction, and a ‘high salt’ cell that produces aversion. What we show is that in flies, salt affects all five identified types of taste cells. There are two low salt cell types and two high salt cell types, and the fifth is a previously identified cell that is actually inhibited by salt and other solutes. This means that salt is encoded in a fundamentally different way than other tastes, which typically activate only a single cell type. We also found that one of the high salt cell types only produced avoidance of salt when the fly had already consumed enough of it. This demonstrates that the complex code of salt taste is also impacted by internal salt need.
What are the next steps for this research?
The biggest open question surrounds a peculiar detail about one of the high salt cells we identified. These cells utilize a different neurotransmitter than all the other taste cells. If we can figure out the importance of this difference to the function of these cells it will tell us a lot about the mechanisms used by the fly brain to process salt information downstream of the sensory neurons.
This research was funded by:
We are very grateful for generous funding from CIHR and NSERC, as well as the Michael Smith Foundation for Health Research.