Blockade of the Dopamine D(3) Receptor Attenuates Opioids-Induced Addictive Behaviours Associated with Inhibiting the Mesolimbic Dopamine System

Opioid use disorder (OUD) has become a considerable global public health challenge; however, potential medications for the management of OUD that are effective, safe, and nonaddictive are not available.

Accumulating preclinical evidence indicates that antagonists of the dopamine D(3) receptor (D(3)R) have effects on addiction in different animal models.

We have previously reported that YQA14, a D(3)R antagonist, exhibits very high affinity and selectivity for D(3)Rs over D(2)Rs, and is able to inhibit cocaine- or methamphetamine-induced reinforcement and reinstatement in self-administration tests.

In the present study, our results illustrated that YQA14 dose-dependently reduced infusions under the fixed-ratio 2 procedure and lowered the breakpoint under the progressive-ratio procedure in heroin self-administered rats, also attenuated heroin-induced reinstatement of drug-seeking behavior.

On the other hand, YQA14 not only reduced morphine-induced expression of conditioned place preference but also facilitated the extinguishing process in mice.

Moreover, we elucidated that YQA14 attenuated opioid-induced reward or reinforcement mainly by inhibiting morphine-induced up-regulation of dopaminergic neuron activity in the ventral tegmental area and decreasing dopamine release in the nucleus accumbens with a fiber photometry recording system.

These findings suggest that D(3)R might play a very important role in opioid addiction, and YQA14 may have pharmacotherapeutic potential in attenuating opioid-induced addictive behaviors dependent on the dopamine system.