ELECTROCHEMICAL INVESTIGATIONS OF DOPAMINE USING ROTATING DISK ELECTRODE VOLTAMMETRY: STUDY OF RELEASE AND REUPTAKE KINETICS AND INHIBITION OF THE NEURONAL DOPAMINE TRANSPORTER

Thesis (Ph.D.), Department of Chemistry, Washington State UniversityThe dopamine transporter (DAT) is the neuronal transporter for the neurotransmitter dopamine (DA). The use of rotating disk electrode voltammetry (RDEV) is a technique used to study transport of DA by DAT. This can be done in normal tissue, as well as tissue samples that have received pharmacological manipulation, such as the addition of the DAT uptake inhibitors cocaine and methamphetamine (METH). In Chapter Two, the rates of exogenous uptake of DA via DAT in rat striatal tissue is studied. Studies are conducted in whole striatal samples, as well as in anterior and posterior sections of striatal tissue to assess variability in DAT function as a function of DA concentration. It is found that the kinetic rates of transport in exogenous tissue vary between anterior and posterior sections, as does the rate of reuptake after stimulation of DA release via KCl addition. Release and reuptake rates of anterior and posterior striatum vary, suggesting that DAT is not kinetically regulated by available local DA concentrations.Chapter Three details studies on the differences of release and subsequent reuptake of DA via DAT in response to METH and amphetamine (AMPH) stimulation. A comparison of the amount of DA released, as well as release and reuptake rates, is presented. Findings suggest that AMPH stimulation causes a similar concentration of DA to be released in comparison to METH, while METH caused greater reduction of DA uptake. AMPH salts such as Ritalin are common medications for children with ADHD, and alternative therapeutic measures for ADHD management are discussed.Chapter Four presents analysis of DAT function in hooded rats afflicted with Parkinson's symptoms. Transport rates of exogenous DA uptake, as well as stimulated DA release and subsequent reuptake, are measured. DAT kinetic function is shown to be retained in Parkinson's rats, suggesting that the transporter is unaffected by the disease in the striatal tissue.Chapter Five presents a brief overview of the work discussed, along with conclusions and future work.Department of Chemistry, Washington State Universit