A Study of the Effects of Dopaminergic Manipulations and Stress on Dynorphin Concentrations in Midbrain and Forebrain Regions of Rat Brain
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Authors
Cho, William
Issue Date
1988
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
In the present study, the effects of stress and dopaminergic manipulations on
dynorphin peptides were investigated in the striatum (Str), substantia nigra (SN),
nucleus acumbens (NA), and ventral tegmental area (VTA) of rat brain because of a
recent history of conflicting reports regarding the effects of stress and dopaminergic
manipulations on these brain regions. Male Sprague-Dawley rats were given repeau()
injections of the dopamine (DA) agonist, apomorphine, followed by a 30 minute
exposure to swimming stress over a course of 14 days; repeated injections of
haloperidol, a DA antagonist, and swim for 14 days; and repeated swim for 7 days
followed by an acute amphetamine challenge. Animals treated simultaneously with
swim and apomorphine showed significant elevations in strlatallevels of Dyn AI-17
and Dyn B, suggesting that an interaction between swimming stress and
apomorphine causes increases in dynorphin levels. Also, across the brain regions,
large differences in peptide concentrations were noted. The SN exhibited 2 to
12-fold greater concentrations over VTA, and that NA consistently contained 2 to
3-fold greater concentrations than Str in all four Prodyn peptides. Dyn AI-8:Dyn
AI-17 ratios were approximately 10:1 and 12:1 in Str and SN, respectively, and
approximately 4: 1 and 2: 1 in NA and VT A, respectively, which implies the existence
of separate dopamine/dynorphin loops between SN and Str and between VT A and
NA.
Description
vi, 43 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.