Coadministration of intravenous nicotine and oral alcohol in rats.

RATIONALE AND OBJECTIVES: Alcohol and nicotine are the most commonly abused drugs, and they are often taken together. We have developed a procedure in which rats self-administer nicotine intravenously and alcohol orally during the same operant session. METHODS: Male Wistar rats were trained to self-administer alcohol (12%, w/v; 0.19 ml/alcohol delivery) or implanted with jugular catheters and trained to self-administer nicotine (30 microg/kg i.v./infusion) by pressing a lever or were trained to self-administer both drugs, some with alcohol first, and others with nicotine first. The effects of extinction of responding for either or both drugs in animals trained to coadminister alcohol and nicotine and the effects of alcohol and nicotine primes on reinstatement were also determined. RESULTS: Animals readily coadministered alcohol and nicotine concurrently. Access to alcohol reduced nicotine self-administration significantly. When responding for alcohol was extinguished with nicotine still available, extinction of alcohol seeking was slowed significantly. In rats trained to coadminister nicotine and alcohol, priming with nicotine or alcohol reinstated extinguished responding for both drugs. Reinstatement of extinguished nicotine or alcohol seeking by, respectively, nicotine or alcohol priming was unaffected by continued access to the other drug. CONCLUSIONS: These results show that rats will self-administer relevant amounts of intravenous nicotine and oral alcohol concurrently. They also provide further support for the important relationship between nicotine and alcohol.