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Imaging brain regional and cortical laminar effects of selective D3 agonists and antagonists
- Source :
- Psychopharmacology. 212:59-72
- Publication Year :
- 2010
- Publisher :
- Springer Science and Business Media LLC, 2010.
-
Abstract
- Dopamine D3 receptors (D3R) may be important therapeutic targets for both drug abuse and dyskinesias in Parkinson’s disease; however, little is known about their functional circuitry. We wished to determine if D3R antagonists SB-277011 and PG-01037 and D3R-preferring agonist 7-OH-DPAT are D3R selective in vivo. We further wished to characterize the response to D3R drugs using whole brain imaging to identify novel D3R circuitry. We investigated D3R circuitry in rats using pharmacologic MRI and challenge with selective D3R antagonists and agonist at various doses to examine regional changes in cerebral blood volume (CBV). We compared regional activation patterns with D2R/D3R agonists, as well as with prior studies of mRNA expression and autoradiography. D3R antagonists induced positive CBV changes and D3R agonist negative CBV changes in brain regions including nucleus accumbens, infralimbic cortex, thalamus, interpeduncular region, hypothalamus, and hippocampus (strongest in subiculum). All D3R-preferring drugs showed markedly greater responses in nucleus accumbens than in caudate/putamen consistent with D3R selectivity and contrary to what was observed with D2R agonists. At high doses of D3R agonist, functional changes were differentiated across cortical laminae, with layer V–VI yielding positive CBV changes and layer IV yielding negative CBV changes. These results are not inconsistent with differential D1R and D3R innervation in these layers respectively showed previously using post-mortem techniques. MRI provides a new tool for testing the in vivo selectivity of novel D3R dopaminergic ligands where radiolabels may not be available. Further, the functional D3R circuitry strongly involves hypothalamus and subiculum as well as the limbic striatum.
- Subjects :
- Male
Agonist
Tetrahydronaphthalenes
Pyridines
medicine.drug_class
Agonist-antagonist
Striatum
Nucleus accumbens
Article
Rats, Sprague-Dawley
Limbic system
Tetrahydroisoquinolines
Nitriles
Basal ganglia
medicine
Animals
Pharmacology
Blood Volume
Dose-Response Relationship, Drug
Chemistry
Putamen
Receptors, Dopamine D3
Subiculum
Brain
Magnetic Resonance Imaging
Rats
medicine.anatomical_structure
Benzamides
Dopamine Agonists
Dopamine Antagonists
Neuroscience
Subjects
Details
- ISSN :
- 14322072 and 00333158
- Volume :
- 212
- Database :
- OpenAIRE
- Journal :
- Psychopharmacology
- Accession number :
- edsair.doi.dedup.....d86820e7792964490c22f72b6c13921b
- Full Text :
- https://doi.org/10.1007/s00213-010-1924-6