Contextual extinction of drug‐associated discriminative stimuli fails to attenuate drug‐vs‐food choice in rhesus monkeys

Abstract

Relapse within the context of a substance use disorder can be triggered by cues that function as discriminative stimuli to signal contingencies of drug availability and promote drug‐taking behavior. Extinction procedures can weaken this association between drug‐associated cues and drug‐taking behavior and may reduce the probability of relapse. This study evaluated a regimen of extinction training on cocaine and heroin self‐administration in rhesus monkeys under a drug‐vs‐food choice procedure. Behavior was initially maintained under a concurrent schedule of food (1‐g food pellets; fixed‐ratio 100 schedule) and cocaine injections (0–0.1 mg/kg/injection; fixed‐ratio 10) (n = 4 males) or heroin injections (0–0.01 mg/kg/injection; fixed‐ratio 10) (n = 3 females and 1 male) during daily 2‐hr choice sessions. Subsequently, choice sessions were supplemented by daily 20‐hr saline self‐administration sessions for 14 consecutive days. During saline self‐administration sessions, only drug‐associated discriminative stimuli were presented and responding produced saline injections. Drug continued to be available during choice sessions. Prior to extinction training, both cocaine and heroin maintained dose‐dependent increases in drug‐vs‐food choice. Exposure to 14 saline self‐administration sessions failed to significantly decrease drug choice and increase food choice. These preclinical results do not support the effectiveness of extinguishing drug‐associated discriminative stimuli as a nonpharmacological treatment strategy for reducing drug choice.