PT  - JOURNAL ARTICLE
AU  - Christopher L. Robison
AU  - Nicole Cova
AU  - Victoria Madore
AU  - Tyler Allen
AU  - Scott Barrett
AU  - Sergios Charntikov
TI  - Assessment of ethanol and nicotine interactions using a reinforcer demand modeling with grouped and individual levels of analyses in a long-access self-administration model
AID  - 10.1101/2022.10.17.512519
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.10.17.512519
4099  - http://biorxiv.org/content/early/2022/10/21/2022.10.17.512519.short
4100  - http://biorxiv.org/content/early/2022/10/21/2022.10.17.512519.full
AB  - Background Previous reports show that both nicotine and ethanol can affect each other’s rewarding and reinforcing effects but there is a lack of studies using methodological approaches that resemble the use of these substances in a vulnerable population.Methods Rats first self-administered ethanol, and their sensitivity to the reinforcing effects of ethanol is assessed using a reinforcer demand modeling. Rats were then equipped with intravenous catheters, allowed to self-administer nicotine, and their sensitivity to the reinforcing effects of nicotine is also assessed using a reinforcer demand modeling. In the final phase of the study, rats are allowed to self-administer ethanol and nicotine concurrently, and the effect of one substance on the rate of responding for another substance is also assessed.Results Our grouped assessments showed that a) ethanol was a stronger reinforcer than nicotine, b) nicotine increased self-administration of ethanol, and c) ethanol decreased self-administration of nicotine. Our individual assessments showed that a) individual demand for sucrose predicted demand for sweetened ethanol, b) individual demand for ethanol did not predict demand for nicotine, c) nicotine demand parameters predicted responding for ethanol when nicotine was available concurrently, and d) ethanol demand parameters did not predict responding for nicotine when ethanol was available concurrently.Conclusions Our study presents one of the ways to model ethanol and nicotine co-use and one of the ways to assess their interaction effects with the help of reinforcer demand modeling and concurrent self-administration or noncontingent administration tests.Competing Interest StatementThe authors have declared no competing interest.