Amphetamine reward in the monogamous prairie vole

Abstract

Recent studies have shown that the neural regulation of pair bonding in the monogamous prairie vole (Microtus ochrogaster) is similar to that of drug seeking in more traditional laboratory rodents. Therefore, strong interactions between social behavior and drug reward can be expected. Here, we established the prairie vole as a model for drug studies by demonstrating robust amphetamine-induced conditioned place preferences in this species. For both males and females, the effects of amphetamine were dose-dependent, with females being more sensitive to drug treatment. This study represents the first evidence of drug reward in this species. Future studies will examine the effects of social behavior on drug reward and the underlying neurobiology of such interactions.

Figure 1

Amphetamine induced conditioned place preference in male and female prairie voles. a) For males, control subjects (n = 5) showed an inherent preference for the environment that would subsequently serve as the saline environment (open bar). AMPH conditioning at 0.1mg/kg (n = 8) failed to induce CPP. Higher doses (0.5mg/kg: n = 8; 1.0mg/kg: n = 8; and 3.0mg/kg: n = 8) induced robust CPP – animals spent significantly more time in the drug paired environment (filled bar). b) For females, controls showed no inherent environmental preference. Low dose administration of AMPH (0.1mg/kg; n = 8) resulted in a trend toward a preference for the drug paired environment, whereas 0.5mg/kg (n = 8) induced a robust CPP. Higher doses of AMPH (1.0mg/kg: n = 7 and 3.0mg/kg: n = 6) failed to induce CPP. Difference scores were based on the pre-test data from each individual subject. * = p < 0.05; Δ = p<0.10; error bars indicate standard error from the mean.