Assessment of the aversive and rewarding effects of alcohol in Fischer and Lewis rats

Abstract

Compared to Fischer, Lewis rats are less sensitive to alcohol's aversive effects as assessed in the CTA paradigm. The behavioral differences observed are not due to hypothermia, but pharmacokinetic differences may contribute. These data underscore the importance of genetic factors and the aversive effects of initial drug exposures in modeling vulnerability to abuse. In addition to its application with other drugs, the Fischer-Lewis model may be useful for investigating the biobehavioral bases of alcohol abuse.

Incentive salience of cocaine across the postpartum period of the female rat

“…Nearly all postpartum females (83%) expressed robust chamber preference for 5 mg/kg IP cocaine, but only approximately half of the postpartum females preferred the cocaine-associated chamber associated with higher doses (10-20 mg/kg) and the lowest (0.5 mg/kg) dose tested. Although CPP has been considered to be relatively insensitive to dose manipulations (Bevins 2005;Bevins and Cunningham 2006), the present study supports previous reports of consistent relationships between varied drug doses and CPP or CPP effect size (Bardo et al 1995;Roma et al 2006;Davis et al 2007;Rezayof et al 2007). …”

Dissociation between the aversive and pharmacokinetic effects of ethanol in female Fischer and Lewis rats

“…The effect of dose was still amenable to between-groups comparisons, but given ethanol's well-documented aversive effects [8], CTA within any given group was defined as the significant decrease in mean saccharin consumption relative to the first saccharin exposure. The high 1.5 g/kg dose was chosen for the present study based on its previously reported ability to differentiate males of these strains in an identical CTA paradigm [34], whereas the low 1 g/kg dose that did not differentiate the males was used to allow a unique sensitivity to the aversive effects of alcohol in female Fischer or Lewis animals to emerge.…”

“…In addition to the self-administration work described above, our laboratory recently reported an assessment of several motivational and physiological responses to alcohol in male Fischer and Lewis rats [34]. Although no significant place conditioning effects emerged in either strain (as is common with rats, see [12]), the Fischer animals were more sensitive than Lewis subjects to the aversive effects of 1.25 and 1.5 g/kg IP ethanol within a conditioned taste aversion design (CTA; see [6,14,35]).…”

“…Given the increasing emphasis on the biological bases of drug abuse in females [20,25,26,27,43], the purpose of the present study was to contribute relevant data on alcohol in Fischer and Lewis rats. Specifically, adult female animals of both strains were tested under the same CTA design at doses previously reported in males [34], where consumption of a novel saccharin solution was immediately followed by IP injection of 1 or 1.5 g/kg ethanol over multiple conditioning trials. Additional females were administered a 1.5 g/kg dose with blood samples taken at multiple points thereafter.…”

“…Using the inbred Fischer and Lewis rat strains, we previously reported stronger conditioned taste aversions (CTA) in male Fischer rats that could not be predicted by genotypic differences in alcohol absorption [34]. The present study made similar assessments in Fischer and Lewis females via four-trial CTA induced by 1 or 1.5 g/kg intraperitoneal (IP) ethanol (n = 10-12/strain/dose) as well as measures of blood alcohol concentrations (BAC) at 15, 60 and 180 min post-injection with 1.5 g/kg IP ethanol or saline (n = 7-8/strain/dose).…”