Ethanol Vapor Self-administration Reveals that Female Wistar Rats are More Likely to Become High Intensity Binge Users than Male Rats

Abstract

<b>Abstract ID 18546</b> <b>Poster Board 266</b> Alcohol misuse has long been a serious health and social concern. Alcohol binge use can increase escalation of alcohol use in humans, and National Institute on Alcohol Abuse and Alcoholism (NIAAA) has described High Intensity (HI) binge drinking which is consuming twice the alcohol as a binge user in a 2-hour period. Binge and HI binge drinking increase negative health and social outcomes for humans, however there are few animal models exhibiting voluntary self-administration of similar amounts of alcohol. Previous work shows that male rats escalate self-administration of ethanol vapor to the point of becoming dependent and that ∼25% of male Wistar rats binge ethanol vapor to reach blood alcohol levels (BALs) in the 300-450 mg% range (de Guglielmo et&nbsp;al., 2017, George lab unpublished data). However, this study was performed only in male rats and it is unclear if the same phenomenon occurs in females. To address this gap, we evaluated sex differences in ethanol vapor self-administration (EVSA) in Wistar rats. <b>Our hypothesis was that some rats that self-administer ethanol vapor will be High Intensity binge users.</b> Rats were tested under a fixed ratio 1 schedule of reinforcement for 8 hr sessions every other day and the duration of alcohol vapor puff increased every 8 sessions from 2, to 5, to 10 minutes. Rats received 1 puff of ethanol vapor with a 20 s time out period for each nosepoke into the drug associated nosepoke port. Tail blood was collected throughout the experiment and blood alcohol levels (BALs) were measured by gas chromatography. Female rats learned to discriminate between active and inactive nosepokes earlier and more accurately than males. Female rats self-administered more ethanol vapor than males. BALs increased throughout the ethanol vapor sessions, with female levels being higher than males. Our criteria for High Intensity binge use of ethanol vapor is that rats have BALs over 160 mg/dL, which is twice the BAL for meeting binge use criteria (80 mg/dL), after their final 8 hr session of self-administering 10 minute long ethanol vapor puffs. Overall, the present results show that female rats discriminate better between active and inactive nosepokes, have faster acquisition of ethanol vapor self-administration, and binge more than males. These results demonstrate the relevance of the ethanol vapor self-administration model to study binge ethanol use and demonstrate that females are particularly vulnerable to High Intensity binge use of alcohol. Support/Funding Information: 5T32AA007456-39, Dr. Marisa Roberto, The Scripps Research Institute, Neuropsychopharmacology:Multidisciplinary Training 5R01AA022977-08, Dr. Olivier George, University of California San Diego, Alcohol Vapor Self-Administration in Rats, P60AA006420 Scripps Research Alcohol Research Center9s Animal Models Core