The effects of ethanol on diverse components of choice in the rat: reward discrimination, preference and relative valuation.

Alcohol consumption impairs judgment and choice. How alcohol alters these crucial processes is primarily unknown. Choice can be fractionated into different components including reward discrimination, preference and relative valuation that can function together or in isolation depending upon diverse factors including choice context. We examined the diverse components and contextual effects by analyzing the effects of alcohol drinking on choice behavior in a task with a reduced level of temporal and spatial constraints. Rats were trained to drink 10% ethanol during 6 weeks of behavior testing using a combined sucrose-fade and two-bottle free-choice procedure. Two different sucrose pellet outcomes (e.g., constant vs. variable) were presented each week to examine the impact of voluntary drinking on reward-based decision-making. Behavioral contexts of single option, free choice and extinction were examined for each outcome set. Comparisons were made between alcohol and control groups and within the alcohol group over time to inspect choice profiles. Between-group results showed alcohol drinking animals expressed altered place preference and modified sucrose reward approach latencies. The within-group profile showed that alcohol drinking animals can express adequate reward discrimination, preference and incentive contrast during free choice. All of these components were significantly reduced during the context of extinction. Control animals were also impacted by extinction but not as severely. The findings point to a need for a greater focus on the context and the diverse components of choice when examining external and internal factors influencing decision-making during alcohol or other substance of abuse exposure.

Effects of anandamide administration on components of reward processing during free choice.

Previous research has implicated the positive modulation of anandamide, an endocannabinoid neurotransmitter, on feeding behavior. Anandamide is particularly noteworthy as it acts as an endogenous ligand of the CB1 receptor, the same receptor that is activated by tetrahydrocannabinol, the primary psychoactive component in Cannabis sativa. Cannabis legalization in North America has presented with a need to study endocannabinoid agonists and their effects on behavior. Much has yet to be determined in terms of the role of the endocannabinoid system in decision-making scenarios. The research presented here tested the hypothesis that anandamide would augment motivation and reward processing via appetitive and consummatory measures during an operant, foraging task. A three-box design was used in order to provide the animals with a free choice, exploratory foraging environment. Discrimination, preference, and incentive contrast were analyzed as discrete measures of decision-making in the three-box paradigm. Anandamide administration (1mg/kg) was found to significantly increase motivation for the optimal foraging outcome and alter basic processing of reward information involved in discrimination and relative valuation. The positive effects of anandamide on eating behavior and motivation have implications toward possible treatment modalities for patient populations presenting with disorders of motivation. These findings suggest the need for continued investigation of the endocannabinoid system as a central component of motivated behavior.

Cooling down the bath salts: Carvedilol attenuation of methylone and mephedrone mediated hyperthermia.

The use of the synthetic cathinones ("bath salts"), methylone and mephedrone, has been associated with the development of life-threatening hyperthermia. To date, no direct pharmacological intervention to mitigate the hyperthermia induced by synthetic cathinones has been identified. Here, we investigated the effects of the non-selective α1 and ß adrenergic receptor antagonist carvedilol (5mg/kg ip) on established hyperthermia mediated by methylone and mephedrone (30mg/kg sc) in Sprague-Dawley rats. Methylone and mephedrone induced a hyperthermic response that peaked 60min post treatment. The administration of carvedilol 30min after methylone or mephedrone significantly attenuated these hyperthermic responses. Analysis of the Temperature Area Under the Curve (TAUC) demonstrated carvedilol significantly reduced the TAUC associated with methylone or mephedrone alone. The present study provides the first direct pharmacological intervention for the treatment of synthetic cathinone induced hyperthermia.