Ethanol reinforcement elicits novel response inhibition behavior in a model of ethanol dependence

Abstract

Reduced impulse control is a known risk factor for drug abuse vulnerability. Chronic experience with drugs of abuse is suggested to enhance impulsivity and thereby perpetuate addiction. However, the nature of this relationship (directionality, causality) with respect to alcohol use disorder is unclear. The current study aims to evaluate changes in impulsivity during the development of ethanol dependence and subsequent protracted abstinence from excessive ethanol. A widely validated chronic intermittent ethanol-vapor exposure (CIE; 14 h vapor-ON/10 h vapor-OFF) was used to generate ethanol dependence and impulsivity was tested using a differential reinforcement of low rates 15 second (DRL15) schedule using either SUCROSE (palatable modified sucrose pellets) or ETHANOL (10%v/v with 0.125% w/v saccharine sodium, 1.5% w/v sucrose). Reduced efficiency of earning reinforcers (expressed as % reinforcers/responses) is indicative of reduced response inhibition or increased impulsivity. Neither CIE, nor forced abstinence altered efficiency in SUCROSE-CIE rats compared to matched SUCROSE-NonCIE. In contrast, efficiency of reinforcement increased in ETHANOL-CIE compared to ETHANOL-NonCIE during during protracted abstinence. Interestingly, ETHANOL-CIE rats escalated the ETHANOL (not SUCROSE) intake during the weeks of CIE exposure; this effect attenuated over the weeks of protracted abstinence. Taken together, the reinforcer-type is key to identifying changes due to ethanol dependence. In contrast to other drugs of abuse, evidence for reduced impulsivity was obtained in the ethanol dependence model. Finally, the behavioral adaptations under DRL15 appear to be targeted towards maximization of ethanol intake and thus, may overlap with neurological underpinnings of escalation and relapse. Support or Funding Information AA020098, AA06420 and DA034140 Ethanol dependent rodents exhibit escalation of ethanol intake under a differential reinforcement of low rates schedule. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.