Psychopharmacology
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Lapses are brief periods of inattention and reduced alertness which may be a risk factor for car crashes. The Dutch on-the-road driving test is applied to examine effects of CNS drugs on driving, using the standard deviation of lateral position (SDLP) as primary outcome measure. This paper examines the utility of an alternative outcome measure, lapses, to determine the degree to which CNS drugs impair driving. ⋯ In addition to SDLP, the number of lapses is a useful outcome measure to identify treatments that impair driving. Future research should determine the unique contributions of SDLP and lapses in defining the potential risk of CNS drugs on driving.
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Abuse of synthetic cathinones, popularized as "bath salts," has increased dramatically in the USA since their debut in 2010. Preclinical behavioral studies may clarify determinants of the abuse-related effects produced by these compounds. ⋯ All compounds facilitated ICSS at some doses and pretreatment times, which is consistent with abuse liability for each of these compounds. However, efficacies of compounds to facilitate ICSS varied, with methcathinone displaying the highest efficacy and mephedrone displaying the lowest efficacy to facilitate ICSS.
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A stress-induced increase in excitability can result from a reduction in inhibitory neurotransmission. Modulation of gamma-aminobutyric acid (GABA)ergic transmission is an effective treatment for drug seeking and relapse. This study investigated whether baclofen, a GABA(B) receptor agonist, had an impact on morphine-induced conditioned place preference (CPP), extinction, and stress-induced relapse in chronically stressed mice. ⋯ Our results showed that baclofen antagonized the effects of chronic stress on morphine-induced CPP. These findings suggest the potential clinical utility of GABA(B) receptor-positive modulators as an anti-addiction agent in people suffering from chronic stress.
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Controlled Clinical Trial
Acute effects of ayahuasca on neuropsychological performance: differences in executive function between experienced and occasional users.
Ayahuasca, a South American psychotropic plant tea containing the psychedelic 5-HT2A receptor agonist N,N-dimethyltryptamine, has been shown to increase regional cerebral blood flow in prefrontal brain regions after acute administration to humans. Despite interactions at this level, neuropsychological studies have not found cognitive deficits in abstinent long-term users. ⋯ Acute ayahuasca administration impaired working memory but decreased stimulus-response interference. Interestingly, detrimental effects on higher cognition were only observed in the less experienced group. Rather than leading to increased impairment, greater prior exposure to ayahuasca was associated with reduced incapacitation. Compensatory or neuromodulatory effects associated with long-term ayahuasca intake could underlie preserved executive function in experienced users.
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Drug abuse can be conceptualized as choice between drug and nondrug reinforcers in which drug choice is excessive; factors impacting drug taking can be examined using procedures in which subjects choose between drug and an alternative reinforcer. ⋯ These results provide evidence that delaying the delivery of a mu-opioid receptor agonist reduces its potency as a positive reinforcer; more importantly, delaying the delivery of an alternative nondrug reinforcer (e.g., food) enhances the reinforcing potency of the agonist. Thus, understanding the factors that control substance abuse requires examination of contingencies for both drug and nondrug reinforcers.