Glutamate receptors in the dorsal hippocampus mediate the acquisition, but not the expression, of conditioned place aversion induced by acute morphine withdrawal in rats.
OBJECTIVE
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 microg/0.5 microL per side) or AMPA receptor antagonist NBQX (2 microg/0.5 microL 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.


CONCLUSIONS
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.
Hou
Yuan-yuan
YY
State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
Liu
Yao
Y
Kang
Shuo
S
Yu
Chuan
C
Chi
Zhi-qiang
ZQ
Liu
Jing-gen
JG
D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects*; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D008845:Microinjections; D009020:Morphine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000378:metabolism*; D013375:Substance Withdrawal Syndrome / Q000378:metabolism*
D017470:Receptors, Glutamate; D009020:Morphine