Cocaine self-administration in social dyads using custom-built operant conditioning chambers

Area of Science:

• Neuroscience
• Behavioral Pharmacology
• Animal Models of Addiction

Background:

• Traditional intravenous drug self-administration studies isolate subjects, limiting their relevance to human drug use, which often occurs socially.
• Existing operant conditioning chambers are not designed for simultaneous testing of multiple animals, hindering social interaction research.

Purpose of the Study:

• To investigate the impact of social contact on cocaine self-administration patterns in rats.
• To develop and validate custom-built operant chambers for social drug self-administration studies.

Main Methods:

• Male rats were housed in pairs within custom-built social operant conditioning chambers, allowing for visual, olfactory, auditory, and limited tactile contact.
• Subjects self-administered cocaine (0.75mg/kg/infusion) under a fixed interval schedule (10-min interval, 5-min limited hold) for five days.
• Behavioral synchrony was assessed by analyzing quarter-life values (time to 25% of responses) using intraclass correlations.

Main Results:

• No significant changes in the total number of cocaine reinforcers obtained were observed across the five testing days.
• Quarter-life values demonstrated increasing similarity between paired rats over the five days, indicating synchronized self-administration patterns.
• Custom chambers successfully enabled concurrent assessment of social influences on drug intake.

Conclusions:

• Social operant conditioning chambers provide a viable preclinical method for studying social influences on drug self-administration.
• This model effectively approximates conditions of human substance use, offering enhanced translational validity for addiction research.