Repeated apomorphine administration alters dopamine D1 and D2 receptor densities in pigeon basal telencephalon.
When pigeons are repeatedly administered a dose of apomorphine they show an increasing behavioral response, much as rodents do. In birds this expresses itself in an augmented pecking response. This sensitization is assumed to be largely due to a conditioning process. Here we present evidence that sensitization is accompanied by an alteration of the D(1) to D(2) dopamine receptor densities. An experimental group of pigeons was repeatedly injected with apomorphine, and a control group with saline. The basal forebrain tissue, known to be rich in dopamine receptors, was subjected to binding assays using tritiated specific D(1) and D(2) dopamine receptor antagonists. There was a trend towards an increase in D(1) and a significant decrease in D(2) receptor densities in apomorphine-treated birds compared to the saline-treated controls. We conclude that extended apomorphine treatment modifies the D(1) dopamine receptor density in the opposite manner to the D(2) dopamine receptor density.
Acerbo
Martin J
MJ
Experimental Psychology, University of Konstanz, 78457, Konstanz, Germany. mjacerbo@umich.edu
Výboh
Pavel
P
Kostál
Lubor
L
Kubíková
Lubica
L
Delius
Juan D
JD
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001667:Binding, Competitive / Q000187:drug effects / Q000502:physiology; D010856:Columbidae / Q000033:anatomy & histology / Q000502:physiology*; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology; D011869:Radioligand Assay; D011940:Receptor Aggregation / Q000187:drug effects / Q000502:physiology; D017447:Receptors, Dopamine D1 / Q000819:agonists* / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000819:agonists* / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D013687:Telencephalon / Q000187:drug effects* / Q000378:metabolism
D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D001058:Apomorphine; D004298:Dopamine