Electrochemical detection of microcystins, cyanobacterial peptide hepatotoxins, following high-performance liquid chromatography

Characterization of the influence of displacing salts on retention in gradient elution ion-exchange chromatography of proteins and peptides.

Methionine-enkephalin (M-ENK) and leucine-enkephalin (L-ENK) are small endogenous opioid peptides that have been implicated in a wide variety of complex physiological functions, including nociception, reward processing, and motivation. However, our understanding of the role that these molecules play in modulating specific brain circuits remains limited, largely due to challenges in determining where, when, and how specific neuropeptides are released in tissue. Background-subtracted fast-scan cyclic voltammetry coupled with carbon-fiber microelectrodes has proven to be sensitive and selective for detecting rapidly fluctuating neurochemicals in vivo; however, many challenges exist for applying this approach to the detection of neuropeptides. We have developed and characterized a novel voltammetric waveform for the selective quantification of small tyrosine-containing peptides, such as the ENKs, with rapid temporal (subsecond) and precise spatial (10s of micrometers) resolution. We have established that the ...

Multiple Scan Rate Voltammetry for Selective Quantification of Real-Time Enkephalin Dynamics

https://cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/display.files/fileID/13410

Electrochemical and conformational studies of microcystin-LR

Opioid peptides are critically involved in a variety of physiological functions necessary for adaptation and survival, and as such, understanding the precise actions of endogenous opioid peptides will aid in identification of potential therapeutic strategies to treat a variety of disorders. However, few analytical tools are currently available that offer both the sensitivity and spatial resolution required to monitor peptidergic concentration fluctuations in situ on a time scale commensurate with that of neuronal communication. Our group has developed a multiple-scan-rate waveform to enable real-time voltammetric detection of tyrosine containing neuropeptides. Herein, we have evaluated the waveform parameters to increase sensitivity to methionine-enkephalin (M-ENK), an endogenous opioid neuropeptide implicated in pain, stress, and reward circuits. M-ENK dynamics were monitored in adrenal gland tissue, as well as in the dorsal striatum of anesthetized and freely behaving animals. The data reveal cofluctuations of catecholamine and M-ENK in both locations and provide measurements of M-ENK dynamics in the brain with subsecond temporal resolution. Importantly, this work also demonstrates how voltammetric waveforms can be customized to enhance detection of specific target analytes, broadly speaking.

https://pubs.acs.org/doi/pdf/10.1021/acschemneuro.8b00351

Joanne P. Steves

Papers

Reverse-phase separation and electrochemical detection of neuropeptides.