We detect fluctuations of non-electroactive species, including glucose, lactate, and acetylcholine, by quantitatively monitoring subsecond H2O2 evolution at oxidase-modified carbon-fiber microelectrodes using background-subtracted FSCV. These electrodes are used in intact brain tissue to monitor the dynamics of both pharmacologically-evoked and naturally-occurring molecular fluctuations with unprecedented chemical and spatial resolution.
Using this microbiosensor, we have recently monitored spontaneous and evoked glucose fluctuations in response to cocaine administration. A graphical depiction is shown here in rat striatal tissue. The microcapillaries are stained in red, dopamine terminals in green, and astrocytes in blue.
Smith S.K., Lee C.A., Dausch M.E., Horman B.M., Patisaul H.B., McCarty G.S., Sombers L.A. Simultaneous Voltammetric Measurements of Glucose and Dopamine Demonstrate the Coupling of Glucose Availability with Increased Metabolic Demand in the Rat Striatum. ACS Chemical Neurosci., In press. DOI: 10.1021/acschemneuro.6b00363
Lugo-Morales L.Z., Loziuk P.L.*, Corder A.K.*, Toups J.V., Roberts J.G., McCaffrey K.A., Sombers L.A. Enzyme-Modified Carbon-Fiber Microelectrode for the Quantification of Dynamic Fluctuations of Nonelectroactive Analytes Using Fast-Scan Cyclic Voltammetry. Anal. Chem. 2013, 85: 8780-8786.