Meeting Abstract
Pleurobranchaea californica or the california sea owl, has distinctive feeding behaviors, a characterized feeding network and the largest neurons in the animal kingdom. Together these features have made this mollusc an excellent model for studying the connection between neuronal network activity and animal behavior. Many electrophysiology studies characterized the link between the activity of a pair of giant serotonin neurons, the metacerebral cells (MCCs) and the sea owl’s hunger state. These repeatedly identifiable MCCs, allow us to answer basic neuroscience questions about the connection between neuronal excitability and gene expression and tie our findings to observable behavior all with single-cell resolution. The MCCs are also conserved across opistobranch molluscs, and thus can provide insights into the evolution of serotonergic neurons and neuronal feeding networks. Previous studies determined that when molluscs are fed until completely satiated, these MCCs show reduced firing rates, and that P. californica stops both producing and releasing its primary signal molecule serotonin when satiated. We investigated whether changes in RNA expression contribute to this phenotype by comparing single-neuron MCC transcriptomes from hungry and satiated animals. Preliminary data also showed a large number of significantly differentially expressed genes, including different mRNA-binding proteins that are expressed during satiation and hunger states. By promoting translation of mRNA transcripts during hunger or sequestering transcripts to prevent translation during satiation these mRNA binding proteins could contribute to the changes in serotonin synthesis observed in P. californica. This finding suggests a potential new mechanism of regulating neurotransmitter expression and neuronal excitability via post-transcriptional modification of the serotonin pathway genes.
