The measurement of neurotransmitter secretions by living cells, both in living organisms
or in preparations, constitutes an enduring and vexing problem for neuroscientists due to
the large number of substances involved at very low concentrations. An ability to
correlate neurotransmitter secretions with various factors including organismic behavior
would greatly advance our understanding of the organization and functioning of central
nervous systems. This, in turn, has many important implications for the diagnosis and
treatment of disorders of central nervous systems (mainly in humans) as well as for the
design and implementation of information processing and control systems.
The work presented here was undertaken in order to explore a novel approach to this
demanding problem. The objective was to develop a probe capable of measuring
neurotransmitter secretions in real time, at physiologically relevant concentrations, and
non-invasively in situ. Data were obtained using an ultraviolet resonance Raman
spectroscopic analytical technique performed via optical fibers, and were analyzed
primarily with artificial neural networks. To this end, a prototype tunable ultraviolet
resonance Raman system was designed, assembled, comissioned and employed.
A general introduction to the problem and a discussion of existing techniques for
neurotranmitter measurement are given in Part I. In Part n, the analytical method was
shown to allow discrimination between several different neurotransmitters and some of
their precursors, both on the basis of their spectra and the selective resonance
enhancement of their spectra. Optical fibers were characterized with regard to their
suitability for use with pulsed ultraviolet radiation in Part III and on the basis thereof
selected for the construction of optical fiber probes. It was found that the performance
of optical fibers varied greatly when subjected to pulsed ultraviolet radiation, making the
selection of fibers a crucial factor in probe construction. Various design features
influencing the efficiency of optical fiber probes were investigated using both theoretical and empirical techniques. A right-angle geometry using a small diameter excitation fiber
and several larger collection fibers in close proximity produced the most efficient probe.
In Part IV the use of cell secretions as samples modelling in vivo conditions were
investigated. It was also shown that these probes could be inserted via surgically
implanted cannulae into and operated in the crania of experimental male rats without
producing discernable behavioral artifacts. In Part V some signal recovery methods were
investigated and it was shown that artificial neural networks could be used to identify
and quantify neurotransmitters based on their Raman spectra. Part VI contains an
assessment of the neuroprobe using neurotransmitter secreting cultured cells as a model
system. The thesis is concluded with a discussion of the charateristics of an ideal
biosensor, reviews the work done, and highlights some future directions.
This thesis represents my contributions toward the development of a tunable
ultraviolet resonance Raman neurotransmitter probe. Within the scope of this work,
limitations of the available equipment and other resources precluded the complete
development of a high-performance neuroprobe, however, the data presented here
demonstrate proof-of-concept and feasibility. In particular, what has hitherto been
considered impossible - the use of optical fibers for pulsed ultraviolet remote resonance
Raman spectroscopy - has been shown to be distinctly feasible. It has further been
shown that ultraviolet resonance Raman spectroscopy is well-suited to the problem of
resolving a mixture of neurotransmitters in a biological matrix. With the appropriate
state-of-the-art equipment, there is now a very real possibilty of obtaining detection
limits of lx10~9 M for the catecholamine neurotransmitters and 1x10"0" M for the
aliphatic neurotransmitters with 30 s exposure time, thus providing a novel and general
solution to the problem of neurotransmitter measurement. / Graduate and Postdoctoral Studies / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/6171 |
| Date | 11 1900 |
| Creators | Schulze, Georg |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Format | 20198340 bytes, application/pdf |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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