Receptor-Binding Studies of Agonists and Antagonists at the D2 Dopamine Receptor in Bovine Caudate
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Authors
Francis, Jonathan W.
Issue Date
1984
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Antipsychotic drugs are thought to produce their therapeutic effects in schizophrenia by blocking receptors for the neurotransmitter dopamine in the brain. Several
lines of evidence previously indicated, however, that 3H-spiperone labels a heterogeneous population of receptors in radioligand binding studies. In the present study, the ability of various dopaminergic agonists (apomorphine,
bromoergocryptine, and dopamine) and antagonists
(chlorpromazine and clozapine) to inhibit 3H-spiperone
binding was determined under conditions where certain
subpopulations of receptors labeled by this radioligand were
blocked by various masking agents. The masking agents used
were dopamine, clozapine, and the selective serotonergic
antagonist, ketanserin. In the studies where dopamine was
used as a masking agent, there was a statistically
significant increase in the inhibitory potency of clozapine.
Conversely, when clozapine was used as a masking agent, the
inhibitory potency of dopamine was enhanced. Whereas
ketanserin significantly increased the inhibitory potency of
dopamine, it also significantly decreased the inhibitory
potency of clozapine. The results generated by these
investigations suggest that 3H-spiperone labels at least 3
different binding sites in bovine caudate. One group of
sites appears to be serotonergic, while the remaining sites
may be two distinct subpopulations of dopamine receptor
which differ in their affinity for dopamine.
Description
v, 31 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.