The dopamine receptor agonist 7-OH-DPAT modulates the acquisition and expression of morphine-induced place preference.
The present study investigated the effects of systemic administration of the putative dopamine D3 receptor agonist 7-hydroxy-N,N-di-n-propyl-2-aminotetralin (7-OH-DPAT) on the acquisition and expression of morphine-induced place preference in male Wistar rats. Using a a 3-day schedule of conditioning it was found that 7-OH-DPAT in a broad dose range (0.01, 0.25 and 5.0 mg/kg) did not produce significant place preference. However, the administration of either 0.25 or 5.0 mg/kg of 7-OH-DPAT 15 min prior to the exposure to morphine (1 mg/kg) prevented the acquisition of a morphine place preference, whereas the 0.01 mg/kg dose of the dopamine receptor agonist was uneffective. In addition, when 7-OH-DPAT was acutely administered 15 min prior to the testing session of an already established morphine place preference, the 0.01 mg/kg dose prevented the expression of this conditioned response. This effect was not observed with either 0.25 and 5.0 mg/kg doses of this dopamine D3 receptor agonist. It was suggested that the different dose related effects of 7-OH-DPAT on the acquisition and expression of morphine place preference might be related to the intrinsic ability of this agonist for interacting with pre- and postsynaptic dopamine D3 receptors located in limbic projecting areas of the mesencephalic dopamine system, although involvement of dopamine D2 receptors cannot be excluded. The pattern of effects seen with 7-OH-DPAT suggests that it may be useful for treating opiate dependence and craving.
Rodríguez De Fonseca
F
F
Departamento de Psicobiología, Facultad de Psicología, Universidad Complutense, Madrid, Spain.
Rubio
P
P
Martín-Calderón
J L
JL
Caine
S B
SB
Koob
G F
GF
Navarro
M
M
D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D003216:Conditioning, Operant / Q000187:drug effects*; D018491:Dopamine Agonists / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006120:Grooming / Q000187:drug effects; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000633:toxicity*; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D011954:Receptors, Dopamine / Q000187:drug effects / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000378:metabolism; D050637:Receptors, Dopamine D3; D013764:Tetrahydronaphthalenes / Q000494:pharmacology*
D018491:Dopamine Agonists; C493595:Drd3 protein, rat; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D013764:Tetrahydronaphthalenes; D009020:Morphine; C031349:7-hydroxy-2-N,N-dipropylaminotetralin