Abstract: Objective To investigate the effect of u-opioid receptor (MOR) on the process of methamphetamine (METH) - induced behavioral sensitization in mice. Methods The antisense and mismatch oligodeoxynucleotides(ODN) for MOR gene were synthesized and delivered individually to mice by intracerebroventricular injection (i.c.v.). Locomotor activity was detected after acute administration with METH in mice. Effects of repeated intermittent administrations of METH on locomotor activity were measured to observe the effects of MOR on the development of behavioral sensitization to METH. Results MOR ASODN could attenuate the METH-induced hyperlocomotor activity in mice and MOR ASODN-exposed mice failed to sensitize to the METH challenge. Conclusion MOR may play an important neuromodulatory role in METH- induced behavior sensitization.

Key words: u-opioid receptor, Anti sense oligodeoxynucleotide, Methamphetamine, Behavioral sensitization