The Effects of the Selective Kappa Antagonist Nor-Binaltorphimine on Dopaminergic Systems of the Rat Brain and Posterior Pituitary
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Authors
La Vigne, Suzette D.
Issue Date
1990
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
The specific effects of a selective kappa opioid-receptor
antagonist nor-binaltorphimine (nor-bni) on the activity of
nigrostriatal, mesolimbic, tuberoinfundibular and
tuberohypophysial dopamine (DA) neurons were examined in the
rat brain and posterior pituitary. The ability of U50488, a
selective kappa opioid agonist, to reverse the effects of
nor-bni was also investigated in order to determine if
nor-bni was acting specifically at a kappa receptor. DA
neuronal activity was estimated by measuring: (1) DA synthesis
(dihydroxyphenylalanine (DOPA) accumulation after the
administration of an aromatic amino acid decarboxylase
inhibitor), (2) DA metabolism (dihydroxyphenylacetic acid
(DOPAC) concentrations), and (3) plasma levels of prolactin
and a-MSH, hormones know to be regulated by tuberoinfundibular
and tuberohypophysial DA neurons , respectively. Nei ther
U50488 or nor-bni had any effect on the activity of
nigrostriatal or mesolimbic DA neurons, indicating that these
neurons are not regulated by kappa receptors.
Tuberoinfundibular DA neurons were activated by nor-bni, but
this effect was not reversed by U50488 and therefore
represents a non-specific action of nor-bni.
Tuberohypophysial DA neurons are also activated by nor-bni,
and this effect was reversed by U50488, revealing a kappa
receptor-mediated tonic inhibition of tuberohypophysial DA
neurons.
With honors.
With honors.
Description
vi, 42 p.
Citation
Publisher
Kalamazoo College
License
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