Experimental animal models are critical for understanding the genetic, environmental and neurobiological underpinnings of alcohol use disorders. Limited studies investigate alcohol-induced effects on behavior using free-choice paradigms. The aims of the present experiment were to study voluntary alcohol intake using a modified intermittent access paradigm, investigate the effects of voluntary alcohol intake on behavioral profiles in water- and alcohol-drinking rats, and select extreme low- and high-drinking animals for a more detailed behavioral characterization. Sixty outbred male Wistar rats were randomized into water and alcohol groups. Behavioral profiles in the multivariate concentric square field™ (MCSF) test were assessed prior to and after voluntary alcohol intake. The animals had intermittent access to 20% alcohol and water for three consecutive days per week for seven weeks. The results revealed increased alcohol intake over time. No major alcohol-induced differences on behavior profiles were found when comparing water- and alcohol-drinking animals. The high-drinking animals displayed an alcohol deprivation effect, which was not found in the low-drinking animals. High-drinking rats had lower risk-taking behavior prior to alcohol access and lower anxiety-like behavior after voluntary alcohol intake compared to low-drinking rats. In conclusion, the modified intermittent access paradigm may be useful for pharmacological manipulation of alcohol intake. With regard to behavior, the present findings highlights the importance of studying subgroup-dependent differences and add to the complexity of individual differences in behavioral traits of relevance to the vulnerability for excessive alcohol intake.

Alcohol use disorder (AUD) is a worldwide public health problem and a polygenetic disorder displaying substantial individual variation. This work aimed to study individual differences in behavior and its association to voluntary alcohol intake and subsequent response to naltrexone in a seamless heterogenic group of animals. Thus, by this approach the aim was to more accurately recapitulate the existing heterogeneity within the human population. Male Wistar rats from three different suppliers (Harlan Laboratories B.V., RccHan™:WI; Taconic Farms A/S, HanTac:WH; and Charles River GmbH, Crl:WI) were used to create a heterogenic group for studies of individual differences in behavior, associations to intermittent voluntary alcohol intake and subsequent response to naltrexone. The rats were tested in the open field prior to the Y-maze and then given voluntary intermittent access to alcohol or water in the home cage for 6 weeks, where after, naltrexone in three different doses or saline was administered in a Latin square design over 4 weeks and alcohol intake and preference was measured. However, supplier-dependent differences and concomitant skew subgroup formations, primarily in open field behavior and intermittent alcohol intake, resulted in a shifted focus to instead study voluntary alcohol intake and preference, and the ensuing response to naltrexone in Wistar rats from three different suppliers. The results showed that outbred Wistar rats are diverse with regard to voluntary alcohol intake and preference in a supplier-dependent manner; higher in RccHan™:WI relative to HanTac:WH and Crl:WI. The results also revealed supplier-dependent differences in the effect of naltrexone that were dose- and time-dependent; evident differences in high-drinking RccHan™:WI rats relative to HanTac:WH and Crl:WI rats. Overall these findings render RccHan™:WI rats more suitable for studies of individual differences in voluntary alcohol intake and response to naltrexone and further highlight the inherent heterogeneity of the Wistar strain. The overall results put focus on the importance of thoroughly considering the animals used to aid in study design and for comparison of reported results.

Some personality traits and comorbid psychiatric diseases are linked to a propensity for excessive alcohol drinking. The objective of this study was to investigate the association between individual differences in risk-related behaviors, voluntary alcohol intake and preference. Outbred male Wistar rats were tested in a novel open field, followed by assessment of behavioral profiles using the multivariate concentric square field (MCSF) test. Animals were classified into high risk taking and low risk taking on the basis of open-field behavior and into high risk-assessing (HRA) and low risk-assessing (LRA) on the basis of the MCSF profile. Finally, voluntary alcohol intake was investigated using intermittent access to 20% ethanol and water for 5 weeks. Only minor differences in voluntary alcohol intake were found between high risk taking and low risk taking. Differences between HRA and LRA rats were more evident, with higher intake and increased intake over time in HRA relative to LRA rats. Thus, individual differences in risk-assessment behavior showed greater differences in voluntary alcohol intake than risk taking. The findings may relate to human constructs of decision-making and risk taking associated with a predisposition to rewarding and addictive behaviors. Further studies are needed to clarify the relationship between risk-related behaviors, including risk-assessment behavior, and liability for excessive alcohol intake.

Certain personality types and behavioral traits display high correlations to drug use and an increased level of dopamine in the reward system is a common denominator of all drugs of abuse. Dopamine response to drugs has been suggested to correlate with some of these personality types and to be a key factor influencing the predisposition to addiction. This study investigated if behavioral traits can be related to potassium- and amphetamine-induced dopamine response in the dorsal striatum, an area hypothesized to be involved in the shift from drug use to addiction. The open field and multivariate concentric square field™ tests were used to assess individual behavior in male Wistar rats. Chronoamperometric recordings were then made to study the potassium- and amphetamine-induced dopamine response in vivo. A classification based on risk-taking behavior in the open field was used for further comparisons. Risk-taking behavior was correlated between the behavioral tests and high risk takers displayed a more pronounced response to the dopamine uptake blocking effects of amphetamine. Behavioral parameters from both tests could also predict potassium- and amphetamine-induced dopamine responses showing a correlation between neurochemistry and behavior in risk-assessment and risk-taking parameters. In conclusion, the high risk-taking rats showed a more pronounced reduction of dopamine uptake in the dorsal striatum after amphetamine indicating that this area may contribute to the sensitivity of these animals to psychostimulants and proneness to addiction. Further, inherent dopamine activity was related to risk-assessment behavior, which may be of importance for decision-making and inhibitory control, key components in addiction.

The electroorganic synthesis of new quinone sulfonimide derivatives using a conventional batch and a new lab-made electrochemical flow cell, under electrolyte-free conditions was achieved.