Dopamine increases in the nucleus accumbens after contingent and noncontingent
ethanol administration in rats, but the contributions of the core, coreshell
border, and shell subregions to this response are unclear. Also, it is not fully
understood if increases in dopamine under these circumstances are due to the
pharmacological effects of ethanol, stimuli associated with administration, or both.
The studies presented in this dissertation were conducted to investigate
dopamine’s role in each of these accumbal regions during ethanol administration
and presentation of associated stimuli. Using microdialysis, ethanol and
dopamine concentrations in accumbal subregions were measured every five
minutes before, during, and after either experimenter-delivered intravenous
ethanol or operant ethanol self-administration. After intravenous ethanol infusions,
the increase in dopamine in the shell of the accumbens was significantly higher than that observed in the core. During operant ethanol self-administration, the
core, core-shell border, and shell, all exhibited significant increases in dopamine
during transfer of the animal into the operant chamber, with animals trained to
drink sucrose + ethanol showing significantly higher increases when compared to
those trained to drink sucrose alone. Dopamine increased significantly only in the
core-shell border during ethanol consumption, and dopamine levels in the core
and shell responded in a similar manner during all phases of the experiment.
Together, these results suggest that dopamine responses to intravenous ethanol
infusions and operant ethanol self-administration are subregion specific. Also,
while increases in dopamine resulting from intravenous ethanol infusions in naïve
animals appear to be due to the pharmacological effects of the drug, increases in
ethanol-experienced animals during transfer into the operant chamber, and
during ethanol consumption, may also be due to stimuli associated with ethanol administration. / text
| Identifer | oai:union.ndltd.org:UTEXAS/oai:repositories.lib.utexas.edu:2152/6539 |
| Date | 16 October 2009 |
| Creators | Howard, Elaina Charlotte |
| Source Sets | University of Texas |
| Language | English |
| Detected Language | English |
| Format | electronic |
| Rights | Copyright is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works. |
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