Date of Graduation

Fall 2014


Master of Science in Chemistry


Chemistry and Biochemistry

Committee Chair

Kathryn M. Fichter


Although the pathophysiology of depression remains unclear, many current efforts at pharmacological intervention for depression among other psychiatric disorders are based upon G protein coupled receptors (GPCRs). The molecular basis and mechanisms whereby drugs alleviate some of the symptoms of these disorders is unknown. Thus understanding the mechanisms of agonist/drug action on GPCRs will aid in the design of more efficacious therapeutic agents. The goal of this study was to investigate agonist-directed endocytic trafficking using quantum dots. To explore these mechanisms, a quantum dot (QD) probe was designed to specifically bind to a mouse neuroblastoma (N2a) cell line clone stably expressing 5-HT1B. The design of the probe utilized covalent bonding (hydrozone) between oxidized carbohydrate rings on anti-hemagglutinin antibodies to form aldehydes and hydrazide functionalized quantum dots via an adipic acid dihydrazide (ADH) reaction. PEG2000 linkers were used to modify the probes to increase water solubility and prevent nonspecificity in cells. The results showed binding specificity of the quantum dot probe to N-2a cells expressing the 5-HT1B receptor as compared to wild type N2a cells. Cells were treated with different concentrations of agonist (CGS-12066) for different times. Trafficking to early endosomes was studied using confocal microscopy and colocalization analysis. The results indicate that these quantum dot probes can report the kinetics of receptor internalization/endosomal trafficking and colocalization, and thus are good candidates for cell studies.


GPCRs, serotonin, QDs, trafficking, early endosomes, colocalization

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