Trait-like impulsivity does not predict escalation of heroin self-administration in the rat

Abstract

Although high impulsivity on the 5-CSRTT has been shown to predict loss of control over cocaine intake, this does not generalize to a loss of control over heroin self-administration. These findings suggest important distinctions in vulnerability mechanisms underlying cocaine and heroin addiction with trait-like impulsivity playing a role in stimulant but not opiate addiction.

Chronic Corticosterone Exposure during Adolescence Reduces Impulsive Action but Increases Impulsive Choice and Sensitivity to Yohimbine in Male Sprague-Dawley Rats

“…In addition, different forms of impulsivity may increase risk for developing an addiction to specific substances. For example, high innate impulsivity on the 5CSRTT is associated with the development of compulsive cocaine-, but not heroin-seeking behavior (Belin et al, 2008;Economidou et al, 2009;McNamara et al, 2010). On the other hand, impulsive choice on delay-discounting tasks has been associated with risk for developing an addiction to several drugs of abuse, and drug addiction is often characterized by more impulsive behavior (increased use or relapse) under stressful conditions, suggesting that chronic adolescent stress hormone exposure could certainly put individuals at risk for developing addictive disorders (Jentsch and Taylor, 1999;Moeller et al, 2001;de Wit, 2009).…”

Animal Models of Drug Addiction

“…However, all rats subjected to extended access to heroin do not necessarily escalate their intake [122]. Thus, when the upper and lower quartile of a population of Lister-Hooded rats are selected on the basis of the escalation slope (a direct measure of the magnitude of escalation of drug intake over time), marked differences can be observed [122].…”

“…Thus, when the upper and lower quartile of a population of Lister-Hooded rats are selected on the basis of the escalation slope (a direct measure of the magnitude of escalation of drug intake over time), marked differences can be observed [122]. Whereas low escalation (LE) rats show a marked increase in their intake when extended access is introduced and then reach a plateau in their daily drug intake, high escalation (HE) rats tend to show a slower adaptation to extended access, in that they do not increase their intake as quickly as LE rats, but progressively lose control over heroin self-administration (figure 2).…”

“…2. Inter-individual propensity to lose control over heroin intake, after (122) Marked inter-individual differences were revealed when the upper (high-escalation rats, HE, n=5) and lower quartile (low-escalation rats, LE, n=5) of a population of lister hooded rats were selected based on the slope of drug intake over all 18 days of the LgA phase [group: F1,8 = 59.44, P < 0.001]. Thus, HE and LE rats displayed a different profile both in terms of heroin intake (A) and escalation ratio (B) [group x session interaction: F22,176 = 8.26, P < 0.001 and F16,128 = 10.20, P < 0.001, respectively].…”

“…7. High anxiety trait predicts loss of control over cocaine, but not heroin, selfadministration in the rat, after (122) High anxious (HA) and low anxious (LA) rats were selected in the upper and lower 33% of a Lister Hooded population (A & D). Whereas HA did not differ from either LA and the overall population in their escalation of heroin intake throughout 12 sessions of 6 h extended access to the drug (B) HA rats showed a marked increase in their cocaine intake as compared to LA or the overall population (E).…”