Nicotine differentially enhances Reinforcer demand for sucrose, alcohol, and sucrose-sweetened alcohol in male and female Wistar rats.

Objective

Most alcohol is consumed in solution with sweeteners or other carbohydrates. Nicotine produces value-enhancing effects on other reinforcers, including sucrose and alcohol. The present study examined nicotine's value-enhancing effects on sucrose, alcohol, and sweetened alcohol self-administration in male and female rats.

Methods

The present study examined demand for 2% Sucrose, 12% Ethanol, and their combined Blend in two equal cohorts (2017 and 2021) of male and female Wistar rats (n = 60; 30/sex; aged 9 weeks on arrival) across a range of fixed-ratio schedules and following subcutaneous injections of saline, 0.1, or 0.4 mg/kg nicotine.

Results

Sweetening alcohol with sucrose increased alcohol consumption by 70.7-197%, which effect could not be attributed to caloric content alone. 12% Ethanol was more reinforcing in males. Nicotine enhanced the essential value of ethanol in both sexes, and selectively enhanced 2% Sucrose reinforcement in females. This produced a sex-equalizing effect on the essential value of sucrose-sweetened alcohol.

Conclusions

Males and females may be differentially sensitive to the appetitive and pharmacological elements of sweetened-alcohol reinforcement. Nicotine co-use may increase the risk of heavy drinking by amplifying the pharmacologically reinforcing effects of alcohol and may pose a particular risk for heavy consumption of sweetened alcohol in women.