Master's Thesis Defense - Comparison of Different Models of the Diffusion & Reuptake of Neurotransmitters in the Brain
Date: July 31, 2007
Time: 10:00 AM
Location: Bossone Research Enterprise Center, Room: 702
Advisor: Karen Moxon, Ph.D.
Diffusion and uptake processes serve an important role in regulating the extracellular concentration of neurotransmitters in the extracellular microenvironment of the brain. Understanding how these neurotransmitters diffuse through the brain and are taken up by active transporters may lead to a better understanding of the mechanisms of drug delivery as well as pathological conditions in the brain that disrupt the regulation of neurotransmitters. Point source, pore space, and Michaelis Menten models were used to understand the role of diffusion uptake of the monoaminergic neurotransmitters dopamine (DA) and norepinephrine (NE) in-vivo. Programs using Matlab and C++ were developed, based on previous published work by Nicholson and others  to calculate the effect of uptake on diffusion and compared to data recorded in-vivo. The effects of varying the model parameters were ﬁrst examined to better understand their role in altering the concentration of neurotransmitter. The output of the model was then compared to data recorded in-vivo to better understand the role of uptake on diffusion in the brain. In-vivo data were collected by pressure pulse injection of a known amount of DA and NE into the somatosensory cortex of the rat. Our results show that with modest values of uptake, the peak of the diffusion curve may be approximated, but the rise and clearance times are not as well modeled.
 Nicholson, C. Interaction Between Diffusion and Michaelis-Menten Uptake of Dopamine After Iontophoresis in Striatum, May 1995. Biophysical Journal, 68: 1699-1715.
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