Intermittent cocaine use patterns, not total intake, predict cue-induced drug seeking in rats

Area of Science:

• Neuroscience
• Behavioral Science
• Addiction Research

Background:

• Cocaine-associated cues can trigger relapse in humans and animal models.
• Previous studies on cocaine intake and relapse used continuous access, unlike typical human intermittent use.
• Discriminative stimuli (DS) are more effective than conditioned stimuli (CS) in triggering drug seeking.

Purpose of the Study:

• To investigate how session length during intermittent access self-administration influences cocaine seeking.
• To compare the effects of discriminative stimuli (DS) and conditioned stimuli (CS) on cocaine seeking.
• To determine if cumulative cocaine intake or individual use patterns predict relapse vulnerability.

Main Methods:

• Female rats underwent intermittent access (IntA) self-administration with either 2-hour (Short-IntA) or 4-hour (Long-IntA) daily sessions.
• Sessions included alternating periods with (DS+) and without (DS-) cocaine availability, paired with specific stimuli (CS+ and CS-).
• Cocaine seeking behavior was assessed after 4 weeks of abstinence by measuring lever presses in response to presented cues.

Main Results:

• Rats with longer access (Long-IntA) consumed twice as much cocaine as Short-IntA rats.
• Discriminative stimuli (DS+), but not conditioned stimuli (CS+), significantly increased cocaine seeking in both groups.
• Individual cocaine intake patterns (e.g., hourly consumption, burst-like intake, latency) predicted relapse intensity, not total cocaine intake.

Conclusions:

• Under intermittent access conditions, individual cocaine-use patterns are key predictors of cue-induced relapse vulnerability.
• Cumulative cocaine intake does not reliably predict the intensity of cue-induced relapse.
• Assessing individual drug-taking profiles is essential for accurate relapse risk assessment in cocaine addiction.