The selective D3Receptor antagonist VK4-116 reverses loss of insight caused by self-administration of cocaine in rats

Abstract

AbstractChronic psychostimulant use causes long-lasting changes to neural and cognitive function that persist after long periods of abstinence. As cocaine users transition from drug use to abstinence, a parallel transition from hyperactivity to hypoactivity has been found in orbitofrontal-striatal glucose metabolism and striatal D2/D3-receptor activity. Targeting these changes pharmacologically, using highly selective dopamine D3-receptor (D3R) antagonists and partial agonists, has shown promise in reducing drug-taking, and attenuating relapse in animal models of cocaine and opioid use disorder. However, much less attention has been paid to treating the loss of insight, operationalized as the inability to infer likely outcomes, associated with chronic psychostimulant use. Here we tested the selective D3R antagonist VK4-116 as a treatment for this loss in rats with a prior history of cocaine use. Male and female rats were first trained to self-administer cocaine or a sucrose liquid for 2 weeks. After 4 weeks of abstinence, performance was assessed using a sensory preconditioning (SPC) learning paradigm. Rats were given VK4-116 (15 mg/kg, i.p.) or vehicle 30 min prior to each SPC training session, thus creating four drug-treatment groups: sucrose-vehicle, sucrose-VK4-116, cocaine-vehicle, cocaine-VK4-116. The control groups (sucrose-vehicle, sucrose-VK4-116) showed normal sensory preconditioning, whereas cocaine use (cocaine-vehicle) selectively disrupted responding to the preconditioned cue, an effect that was reversed in the cocaine-VK4-116 group, which demonstrating responding to the preconditioned cue at levels comparable to controls. These preclinical findings demonstrate that highly selective dopamine D3R antagonists, particularly VK4-116, can reverse the long-term negative behavioral consequences of cocaine use.