Female rats selectively bred for higher saccharin intake show more rapid and successful acquisition of IV self-administration of a low dose of cocaine than those bred for low saccharin intake. Female rats (compared with males) consistently showed accelerated rates of acquisition and maintenance (PR) of cocaine self-administration and acquisition of heroin self-administration.

A positive relationship between the consumption of sweetened dietary substances (e.g. saccharin and sucrose) and drug abuse has been reported in both the human and other animal literature. The proposed genetic contribution to this relationship has been based on evidence from behavioral, neurobiological, and linkage studies in heterogeneous and homogeneous animal populations. Initial work in several laboratories indicated that rodents that are selected for high alcohol consumption also display an increased preference for sweets compared with low alcohol-consuming animals. More recently, Sprague-Dawley rats have been selectively bred based on high saccharin (HiS) or low saccharin (LoS) consumption, and these lines represent an ideal opportunity to determine whether a reciprocal genetic relationship exists between the consumption of sweetened substances and self-administration of drugs of abuse. The purpose of this review is to examine a series of studies on the HiS and LoS rats for drug-seeking and drug-taking behavior using laboratory animal models that represent critical phases of drug abuse in humans. The data support the hypothesis that sweet consumption and drug self-administration are closely related and genetically influenced. Other characteristics of HiS and LoS rats are discussed as possible mediators of the genetic differences such as activity, impulsivity, novelty reactivity, stress, and emotionality. The interaction of sweet preference with biological variables related to drug abuse, such as age, sex, and hormonal influences, was considered, as they may be additive vulnerability factors with consumption of sweet substances. In the studies that are discussed, the HiS and LoS lines emerge as ideal addiction-prone and addiction-resistant models, respectively, with vulnerability or resilience factors that will inform prevention and treatment strategies for drug abuse.

These results suggest that HiS and LoS rats have distinct drug-seeking and drug-taking profiles. The HiS and LoS rats differ along a wide range of behavioral dimensions and represent an important model to study the interactions of excessive intake of dietary substances and vulnerability to drug abuse.

No abstract

No abstract