The attenuation of morphine-conditioned place preference following chronic mild stress is reversed by a CCKB receptor antagonist.
Chronic exposure to mild unpredictable stress has been found to abolish the acquisition of preference for a distinctive environment paired with morphine, whereas morphine induced conditioning place preference in non-stressed rats. Chronic treatment for 21 days with the tricyclic antidepressant imipramine reversed the motivational effects produced by chronic mild stress, and animals showed a place preference for the morphine-paired compartment. When the CCKB receptor antagonist PD-134,308 was co-administered with morphine in stressed animals during the conditioning period, the preference for the morphine-paired compartment was also re-established. The CCKB receptor antagonist given alone did not induce rewarding effects in this paradigm. These findings indicate that the administration of a CCKB receptor antagonist reversed the effects of chronic mild stress on opiate rewarding properties.
Valverde
O
O
Département de Pharmacologie Moléculaire et Structurale, U266 INSERM, URA D 1500 CNRS, Université René Descartes, URF des Sciences Pharmaceutiques et Biologiques, Paris, France.
Smadja
C
C
Roques
B P
BP
Maldonado
R
R
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D007211:Indoles / Q000494:pharmacology*; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives* / Q000494:pharmacology; D009020:Morphine / Q000494:pharmacology*; D051381:Rats; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors*; D013312:Stress, Physiological / Q000523:psychology*; D013997:Time Factors
D007211:Indoles; D011949:Receptors, Cholecystokinin; C065599:PD 134308; D008536:Meglumine; D009020:Morphine