DOI
https://doi.org/10.25772/501D-JC95
Defense Date
2014
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Pharmaceutical Sciences
First Advisor
Douglas Sweet
Abstract
According to the World Health Organization, mental disorders represent the leading cause of disability in the US generating ~58 billion dollars in medical costs annually. Additionally, among the US population, ~40 million adults suffer from an anxiety disorder and ~14 million suffer from a major depressive disorder. The association between the persistence of these neurobehavioral conditions and central nervous system (CNS) levels of biogenic amines and metabolites has been studied for half a century. Further, a number of drugs interfering with neurotransmission/metabolism are used clinically for treatment of these disorders. Recently, some members of the solute carrier (SLC) superfamily, the SLC22 transporter family, which includes organic anion transporters (Oat1, Oat3), were found to be expressed and functional on the apical membrane of the choroid plexus, a component of the blood-cerebrospinal fluid barrier. The cells of this epithelia form tight junctions, which slows penetration of solutes into the brain and limits passive efflux of endogenous solutes from the brain. Therefore, Oat1 and Oat3 are poised to play an active role in the removal of NTs and metabolites from the CSF. Thus, a better understanding of the underlying roles of OATs in regulating CNS neurotransmitters and connecting their activity to complex behaviors may result in improved understanding of the processes governing CNS homeostasis. Basal locomotor, anxiety-like and depressive-like behaviors in mice of three genotypes (WT, Oat1-/-, and Oat3-/-) across ages (3-18 mo.) were evaluated using behavioral paradigms (e.g. open field activity (OFA), light-dark (LD), marble burying (MB), and tail suspension test (TST)). Secondly, a simple high performance liquid chromatography-ultraviolet/electrochemical detection (HPLC-UV/ECD) method was developed for quantitation of monoamines and metabolites in mouse whole brain. Following completion of behavioral assessments, whole brain concentrations of monoamines and metabolites were determined using the developed method. Lastly, a novel gas chromatography tandem mass spectrometry (GC-MS/MS) method was developed for quantitation of amino acid neurotransmitters, L-glutamic acid (GA) and γ-aminobutyric acid (GABA), in mouse whole brain. The developed method was used for measurement of whole brain concentrations of GA and GABA in a small subset of WT, Oat1-/-, and Oat3-/- mice at 3 and 18 mo.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
8-20-2014