The mu opioid receptor is involved in buprenorphine-induced locomotor stimulation and conditioned place preference

Area of Science:

• Pharmacology
• Neuroscience

Background:

• Buprenorphine's analgesic effects are known to be mediated by the mu opioid receptor (MOP).
• The specific role of MOP in buprenorphine's non-analgesic effects, such as locomotor stimulation and reward, remains to be fully elucidated.

Purpose of the Study:

• To investigate the role of the mu opioid receptor (MOP) in mediating buprenorphine-induced locomotor stimulation and conditioned place preference (CPP).

Main Methods:

• Utilized MOP knockout mice and their wild-type littermates.
• Assessed locomotor activity following acute and repeated buprenorphine administration.
• Evaluated conditioned place preference (CPP) using a standard drug-CPP paradigm.
• Administered buprenorphine (3 mg/kg) and amphetamine (1 mg/kg) for behavioral testing.

Main Results:

• Buprenorphine increased motor activity in wild-type mice but not in MOP knockout mice, indicating MOP mediation of motor stimulation.
• Sensitization to the motor stimulatory effects of buprenorphine developed in wild-type mice but not in MOP knockout mice.
• Buprenorphine induced CPP in wild-type mice, an effect absent in MOP knockout mice.
• Amphetamine induced comparable CPP in both wild-type and MOP knockout mice.

Conclusions:

• The mu opioid receptor (MOP) is essential for buprenorphine's motor stimulatory effects.
• MOP mediates the development of locomotor sensitization to buprenorphine.
• Buprenorphine-induced conditioned place preference (CPP) is critically dependent on the mu opioid receptor (MOP).