Acta Pharmacologica Sinica (2009) 30: 1385-1391; doi: 10.1038/aps.2009.130

Acta Pharmacologica Sinica (2009) 30: 1385-1391; doi: 10.1038/aps.2009.130; published online 21 Sep 2009

Original Article

Glutamate receptors in the dorsal hippocampus mediate the acquisition, but not the expression, of conditioned place aversion induced by acute morphine withdrawal in rats

Yuan-yuan HOU, Yao LIU, Shuo KANG, Chuan YU, Zhi-qiang CHI, Jing-gen LIU*

State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China

Aim: To evaluate the role of glutamate receptors in the dorsal hippocampus (DH) in the motivational component of morphine withdrawal.

Methods: NMDA receptor antagonist D-AP5 (5 μg/0.5 μL per side) or AMPA receptor antagonist NBQX (2 μg/0.5 μL per side) was microinjected into DH of rats. Conditioned place aversion (CPA) induced by naloxone-precipitated morphine withdrawal were assessed.

Results: Preconditioning microinjection of D-AP5 or NBQX into the DH impaired the acquisition of CPA in acute morphine-dependent rats. However, intra-DH microinjection of D-AP5 or NBQX after conditioning but before the testing session had no effect on the expression of CPA.

Conclusion: Our results suggest that NMDA and AMPA receptors in the dorsal hippocampus are involved in the acquisition, but not in the expression, of the negative motivational components of acute morphine withdrawal in rats.

Keywords: NMDA receptors; AMPA receptors; hippocampus; morphine withdrawal; conditioned place aversion; Rats, Sprague-Dawley; microinjections

This study was supported by the National Basic Research Program grant from the Ministry of Science and Technology of China (No G2003CB515400) and (No 2009CB522000), National Science Fund for Distinguished Young Scholar from the National Natural Science Foundation of China (No 30425002) and a fund granted by the Chinese Academy of Sciences (No KSCXI/YW/R/68).

* To whom correspondence should be addressed.
Emal jgliu@mail.shcnc.ac.cn
Received 2009-05-19 Accepted 2009-07-15

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