RESUMO
OBJECTIVE: The present study evaluated the effects of nicotine concentration (0-10 mg/ml) and flavor (gummy bear vs unflavored) on the subjective experiences of vaporized nicotine in young adult low-dose nicotine (3 mg/ml) ECIG users. PARTICIPANTS: Eight young adult ECIG users were recruited. METHODS: A single blinded crossover study was used. Participants were instructed to take ten 1.5 second puffs, each separated by 20 seconds. After self-administration, heart rate was recorded, and participants completed the Drug Effects, Direct Effects of Nicotine, and Direct Effects of ECIG questionnaires. RESULTS: ECIG user's standard daily nicotine dose influenced the rewarding and aversive effects of nicotine as the 10 mg/ml dose was found to be aversive in this user group. The combination of flavor and nicotine increased the subjective effects of ECIGs. CONCLUSIONS: Flavored e-liquids contribute to the reinforcing properties of nicotine by enhancing the subjective effects, which may lead to continued ECIG use.
RESUMO
The effectiveness of ketamine for treatment-resistant depression along with several other clinical advantages, such as rapid onset and reduced adverse effects associated with serotonin transporter inhibition, has garnered interest in other similar acting psychedelics as novel antidepressant drugs. The antitussive dextromethorphan exhibits glutamate N-methyl-d-aspartate receptor antagonism, sigma-1 receptor agonism, and serotonin reuptake inhibition, which has exhibited antidepressant effects in limited human studies and animal models. The present study sought to further examine dextromethorphan using a differential reinforcement of low-rate 72-s schedule, which can be used to screen antidepressant drugs, in male and female rats. The tricyclic antidepressant drug imipramine and the psychostimulant d-amphetamine also were examined. Sex differences were not shown for baseline performance or for the drugs tested. Further, performance did not differ between the estrus and diestrus stages. Dextromethorphan alone and with quinidine produced an antidepressant-like effect by reducing the number of responses emitted, increasing the number of reinforcers earned, and shifting inter-response times to the right, although significant response suppression occurred at these doses. An antidepressant-like effect was shown with imipramine, but d-amphetamine increased the number of responses emitted and did not affect the number of reinforcers earned. The present findings provide additional support for antidepressant effects produced by dextromethorphan.
