Female Rats Display Enhanced Rewarding Effects of Ethanol That Are Hormone Dependent
Article first published online: 1 AUG 2013
Copyright © 2013 by the Research Society on Alcoholism
Alcoholism: Clinical and Experimental Research
How to Cite
Torres, O. V., Walker, E. M., Beas, B. S. and O'Dell, L. E. (2013), Female Rats Display Enhanced Rewarding Effects of Ethanol That Are Hormone Dependent. Alcoholism: Clinical and Experimental Research. doi: 10.1111/acer.12213
- Article first published online: 1 AUG 2013
- Manuscript Accepted: 14 MAY 2013
- Manuscript Received: 10 AUG 2012
- UTEP Office of Research and Sponsored Projects
- Minority Access to Research Careers Program. Grant Number: 2T34GM008048
- Bridges to the Baccalaureate Program. Grant Number: 5R25GM049011-12
- National Institute on Drug Abuse. Grant Numbers: R01-DA021274, R24-DA029989, R25-DA033613
- National Institute of Minority Health Disparities. Grant Number: G12MD007592
- UTEP Dodson Doctoral Fellowship Program
- Sex Differences
Ethanol (EtOH) abuse is a major health and economic concern, particularly for females who appear to be more sensitive to the rewarding effects of EtOH. This study compared sex differences to the rewarding and aversive effects of EtOH using place-conditioning procedures in rats.
Separate groups of adult (male, female, ovariectomized [OVX] female) and adolescent (male and female) rats received EtOH (0, 0.5, 1.0, 2.0, or 2.5 g/kg, intraperitoneal) and were confined to their initially nonpreferred side of our conditioning apparatus for 30 minutes. On alternate days, they received saline and were confined to the other side. Following 5 drug pairings, the rats were retested for preference behavior. Separate cohorts of the same groups of rats were injected with a similar dose range of EtOH, and blood EtOH levels (BELs) were compared 30 minutes later.
EtOH produced rewarding or aversive effects in a dose-dependent manner. An intermediate dose of EtOH (1.0 g/kg) produced rewarding effects in adult female, but not in male or OVX female rats, suggesting that ovarian hormones facilitate the rewarding effects of EtOH. Similarly, this intermediate dose of EtOH produced rewarding effects in adolescent female, but not in male rats. The highest dose of EtOH (2.5 g/kg) produced aversive effects that were similar across all adult groups. However, the aversive effects of EtOH were lower in adolescents than adults, suggesting that adolescents are less sensitive to the aversive effects of EtOH. The aversive effects of EtOH did not vary across the estrous cycle in intact adult females. There were also no group differences in BELs, suggesting that our results are not related to EtOH metabolism.
Our results in rats suggest that human females may be more vulnerable to EtOH abuse due to enhanced rewarding effects of this drug that are mediated by the presence of ovarian hormones.