“To Fluoresce or Not to Fluoresce: An Investigation of Neurochemicals Implicated in Anxiety using CE-LIF”

Dr. Rachel Saylor, Assistant Professor of Chemistry and Biochemistry, Oberlin College

Abstract: 

Primary amines are ubiquitous in biological systems and responsible for countless important processes, including neurotransmission and cell signaling, and diseases and disorder states, including anxiety and depression.  These molecules have been sensitively detected via fluorescence after their reaction with the fluorogenic reagent naphthalene-2,3-dicarboxaldehyde (NDA) in the presence of cyanide through the formation of fluorescent N-substituted 1-cyanobenz[f]isoindole (CBI) derivatives.  However, practically we have observed several challenges in routine use of this reaction, including the lack of fluorescence from derivatized primary amines dopamine and serotonin, both of which are important neurotransmitters associated with many neurological disease states, including anxiety.  To interrogate these complications and provide improvements to this reaction, we screened a cohort of primary amines for their fluorescence characteristics under various conditions using fluorescence spectroscopy and their structure using nuclear magnetic resonance spectroscopy.  We propose structural characteristics implicated in the lack of fluorescence in select CBI-amines, and develop methods to recover their fluorescence.  Finally, we implement our methods in combination with capillary electrophoresis and laser-induced fluorescence detection for the determination of over ten primary amines present in the model organism Caenorhabditis elegans. In the future, this work will serve as a basis for interrogating the connection between neurologically relevant primary amine concentrations and anxiety-like behavior in Caenorhabditis elegans.