In vivo characterization of cocaine mediated regulation of the dopamine transporter
Year: 2024
Type: dissertation
Abstract: The psychostimulant, cocaine, is a highly misused drug. Dependence on cocaine affects over 5 million people in the US. However, there is no approved medication to treat this health issue. Cocaine affects the reward pathway in the brain's limbic system. Dopamine, the key neurotransmitter in this region mediates behaviors involved in motivation, pleasure, and learning. Following its release into the synapse of neurons, dopamine is removed by the dopamine transporter (DAT) present on the presynaptic dopaminergic neurons. Cocaine binds to DAT on the pre-synaptic neuronal cell surface and inhibits the reuptake of dopamine from the synapse. This leads to accumulation of excess dopamine in the synaptic cleft, causing euphoria in the subjects. In addition to DAT, previous studies have also shown that dopamine D2 autoreceptors play an important role in regulating the activity of dopaminergic neurons. In this study we aim to first evaluate the effect of acute cocaine treatment on surface DAT protein expression. Then investigate whether cocaine mediates its action through the D2 autoreceptor feedback mechanism. We also explore the role of Mitogen Activated Protein Kinase Phosphatase 3 (MKP3) in this regulation. To test this, we used in vivo rat models to evaluate cocaine induced hyperactivity and regulation of DAT in the Nucleus Accumbens (NAc). We evaluated DAT protein expression using ex-vivo slice biotin labeling and immunoblotting and correlated DAT expression with locomotion. Our findings suggest that cocaine increases surface DAT expression, and we show that D2 receptors and MKP3 play a significant role in regulating this process. These findings will provide a foundational basis for future studies in understanding the regulation of DAT and its implications in Cocaine Use Disorder.
DOI: 10.17918/00010577
Language: English
Subfield: Cellular and Molecular Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: gold
OpenAlex ID: W4403052185