Rats overexpressing the dopamine transporter display behavioral and neurobiological abnormalities with relevance to repetitive disorders

The dopamine transporter (DAT) plays a pivotal role in maintaining optimal dopamine signaling. DAT-overactivity has been linked to various neuropsychiatric disorders yet so far the direct pathological consequences of it has not been fully assessed. We here generated a transgenic rat model that via pronuclear microinjection overexpresses the DAT gene. Our results demonstrate that DAT-overexpression induces multiple neurobiological effects that exceeded the expected alterations in the corticostriatal dopamine system. Furthermore, transgenic rats specifically exhibited behavioral and pharmaco-therapeutic profiles phenotypic of repetitive disorders. Together our findings suggest that the DAT rat model will constitute a valuable tool for further investigations into the pathological influence of DAT overexpression on neural systems relevant to neuropsychiatric disorders

Sex-associated differences in incentive salience and drinking behaviour in a rodent model of alcohol relapse

The ability of environmental cues to trigger alcohol-seeking behaviours is thought to facilitate problematic alcohol use. Individuals' tendency to attribute incentive salience to cues may increase the risk of addiction. We sought to study the relationship between incentive salience and alcohol addiction using non-preferring rats to model the heterogeneity of human alcohol consumption, investigating both males and females. Adult rats were subjected to the alcohol deprivation effect (ADE) paradigm, where they were given voluntary access to different alcohol solutions with repeated interruptions by deprivation and reintroduction phases over a protracted period (five Alcohol Deprivation Cycles). Before each Alcohol Deprivation Cycle, rats were tested in the Pavlovian Conditioned Approach (PCA) paradigm, which quantifies the individual salience toward a conditional cue and the reward, thus allowing us to trace the process of attributing incentive salience to reward cues. During the final Alcohol Deprivation Cycle (ADE5), animals were tested for compulsive-like behaviour using quinine taste adulteration. We investigated sex differences in drinking behaviour and PCA performance. We observed thatb females drank significantly more alcohol than males and displayed more sign-tracking (ST) behaviour in the PCA, whereas males showed goal-tracking (GT) behaviour. Furthermore, we found that high drinkers exhibited more ST behaviour. The initial PCA phenotype was correlated with later alcohol consumption. Our findings indicate a complex relationship between incentive salience and alcohol addiction and emphasize the importance of considering both sexes in preclinical research.</p

The effect of CEO risk appetite on firm volatility: an empirical analysis of financial firms

This paper examines the effect of CEO risk appetite on the return volatility of a sample of large, listed financial firms over the period 2000-2008. After controlling for firm specific characteristics, the results give strong evidence that the CEO risk appetite has an important effect on firm volatility. The biographical measures for CEO risk appetite are significant explanatory variables of all measures of firm volatility employed in this study. The effect of CEO age is significant and positive for all four volatility measures, while CEO education and current job tenure are negative and significant for all four measures. Executive experience with other firm boards has a negative and significant effect on total and idiosyncratic volatility. Interestingly, CEO wealth is complementary to the other biographical variables with a positive effect on all but the default volatility measure. Our results carry implications for shareholders, financial regulators, governments and managers

Elementary theory of economic behavior

ix, 332 p.; 23 cm