Defense Date


Document Type


Degree Name

Doctor of Philosophy



First Advisor

Louis J. De Felice

Second Advisor

Richard A. Glennon

Third Advisor

Diomedes E. Logothetis

Fourth Advisor

Sidney S. Negus

Fifth Advisor

Ian S. Ramsey


Dysregulation of dopaminergic homeostasis has been established as the primary source of numerous neurological disorders including Parkinson’s and drug addiction. A tonic increase of dopamine (DA) in the nucleus accumbens is required for associating everyday events and behaviors with rewards. Yet many addictive exogenous compounds such as amphetamine (AMPH) and cocaine (COC) produce a much greater augmentation of synaptic DA levels that are linked to euphoria and a shift in behavior towards drug seeking. The protein responsible for maintaining extracellular levels of DA is the dopamine transporter (DAT). It is primarily located in the perisynaptic area at terminals of pre-synaptic neurons where its main function is to sequester DA from the extracellular space and to transport it back into the cell, a process that is electrogenic. AMPH and COC directly interact with DAT and alter its ionic currents. Not much is known about the effect of psychostimulant-induced DAT currents on neuronal excitability and neurotransmitter release. We use synthetic chemistry, molecular biology, and biophysics in heterologous expression systems to decipher the actions of drugs of abuse on DAT. Furthermore we demonstrate drug-induced DAT currents can activate Ca2+ channels associated with dopaminergic excitability. Lastly, we focused on investigating drug effects on excitability in a human midbrain dopaminergic cell line. Understanding how psychostimulants interact with DAT to produce the dysfunctional states of the transporter may facilitate the development of unique therapeutic strategies to treat psychostimulant dependence.


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