Defense Date


Document Type


Degree Name

Master of Science


Physiology and Biophysics

First Advisor

Dr. José-Miguel Eltit


Psychostimulants elicit their psychological and behavioral effects through interactions with the monoamine transporters. These compounds are classified as either substrates or reuptake inhibitors, depending on their mechanism of action, and have varying potencies at the three human monoamine transporters, hDAT, hSERT, and hNET. Substrates and reuptake inhibitors also have distinct electrophysiological signatures: reuptake inhibitors cause hyperpolarization in HEK293 cells stably expressing the monoamine transporters, whereas substrate transport mediates a depolarizing current. Recent studies have shown that substrate-mediated depolarization is sufficient to activate L-type calcium channels, a characteristic which has been used to develop a novel calcium assay which uses calcium signals to measure monoamine transporter activity. In the present study, the calcium assay is used to assess the activity of a series of methcathinone analogs at hSERT and hNET from a structure-activity relationship standpoint. All compounds were found to be significantly weaker at SERT as compared to hDAT, which suggests higher potential abuse liability. SERT appears to be stereospecific with regard to methcathinone analogs and requires a substituent in the S position for drug activity. All compounds were found to be twice as potent at hNET as compared to hDAT. Given the functional relationship between hDAT and L-type calcium channel Cav1.2, this study also sought to characterize the physical interaction between the two proteins. Using a high-resolution technique known as FRET, it was determined that hDAT and Cav1.2 do not colocalize to a significant extent and thus are unlikely to directly interact to form a complex.


© Vy T. Nguyen

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Available for download on Tuesday, August 06, 2024