Role of DRD3 in morphine-induced conditioned place preference using drd3-knockout mice.
The dopamine D3 receptor (DRD3) mediates expression of conditioned effects of psychostimulants, but conflicting results have been obtained with opiates. In a conditioned place preference (CPP) procedure, morphine increased the time spent in a compartment previously paired with drug injection. CPP was obtained at morphine doses of 16 and 32 mg/kg in wild-type (drd3+/+) mice and 8, 16 and 32 mg/kg in DRD3-knockout (drd3-/-) mice. BP897, a DRD3-selective partial agonist, inhibited the expression of morphine-CPP in drd3+/+, but not drd3-/- mice. BP 897 reduced brain regional activation, measured by c-fos imaging after the CPP test session, in the somatosensory cortex of drd3+/+, but not drd3-/- mice. These results confirm the role of DRD3 in the expression of conditioned effects of morphine and the participation of the somatosensory cortex in these effects.
Francès
Henriette
H
Unité de Neurobiologie et Pharmacologie Moléculaire (INSERM U 573), Centre Paul Broca, 75014 Paris, France.
Le Foll
Bernard
B
Diaz
Jorge
J
Smirnova
Maria
M
Sokoloff
Pierre
P
D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005838:Genotype; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009020:Morphine / Q000494:pharmacology*; D017448:Receptors, Dopamine D2 / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D050637:Receptors, Dopamine D3
C493594:Drd3 protein, mouse; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D009020:Morphine