E. Delpozo et al., THE NMDA RECEPTOR ANTAGONIST DIZOCILPINE (MK-801) STEREOSELECTIVELY INHIBITS MORPHINE-INDUCED PLACE PREFERENCE CONDITIONING IN MICE, Psychopharmacology, 125(3), 1996, pp. 209-213
The effect of the non-competitive NMDA receptor antagonist dizocilpine
(MK-801) on conditioned place preference induced by morphine was stud
ied in mice. As expected, morphine (1-8 mg/kg, IP) elicited a signific
ant preference for the drug-paired compartment. Pretreatment of mice w
ith (+)-dizocilpine (0.1 and 0.2 mg/kg, IP), the more active dizocilpi
ne enantiomer, dose-dependently reversed the conditioned place prefere
nce produced by morphine (4 mg/kg, IP), whereas (-)-dizocilpine (0.2 m
g/kg, IP) did not modify morphine-induced effects. In contrast, both e
nantiomers of dizocilpine (at a dose of 0.2 mg/kg, IP) elicited a cond
itioned place preference. These data suggest that (1) NMDA receptors p
lay a role in morphine-induced place preference, and (2) dizocilpine-r
einforcing properties in the place preference paradigm do not seem to
be dependent on NMDA receptor blockade.