Nicotine Enhances Operant Responding for Qualitatively Distinct Reinforcers Under Maintenance and Extinction Conditions

RATIONALE—Nicotine enhancement of reward has been implicated as an important contributor to tobacco addiction. Despite the attention that reward enhancement has received, the behavioral mechanisms whereby nicotine enhances operant responding remain largely unknown. The present study sought to extend previous work by evaluating the effects of nicotine on responding for two qualitatively different rewards (visual stimulation (VS) and 4% sucrose solution) under fixed-ratio (FR) maintenance and extinction conditions. METHOD—Sprague-Dawley rats were trained to press an active lever for VS (Experiment 1) or 4% sucrose solution (Experiment 2) and evaluated over 15 sessions on a FR5 schedule of reinforcement. Nicotine (0.4 mg base/kg, SC) or saline were administered 5 min before each session; the alternate solution was given in the home cage after the session. The effects of nicotine on extinction responding were then assessed over 5 sessions and rats were divided into 4 groups based on drug of injection received during FR-maintenance and extinction phases (Maintenance- Extinction): Nic-Nic, Nic-Sal, Sal-Sal, and Sal-Nic. RESULTS—Nicotine increased active lever response rates for both VS and 4% sucrose under FR5 maintenance conditions. Nicotine also increased response rates in the Nic-Nic group relative to all other groups under extinction conditions in both experiments, though this effect had greater longevity following VS maintenance conditions than sucrose. Enhancement of responding during extinction does not appear dependent upon locomotor activation by nicotine

A quantitative analysis of the reward-enhancing effects of nicotine using reinforcer demand

Reward enhancement by nicotine has been suggested as an important phenomenon contributing toward tobacco abuse and dependence. Reinforcement value is a multifaceted construct not fully represented by any single measure of response strength. The present study evaluated the changes in the reinforcement value of a visual stimulus in 16 male Sprague–Dawley rats using the reinforcer demand technique proposed by Hursh and Silberberg. The different parameters of the model have been shown to represent differing facets of reinforcement value, including intensity, perseverance, and sensitivity to changes in response cost. Rats lever-pressed for 1-min presentations of a compound visual stimulus over blocks of 10 sessions across a range of response requirements (fixed ratio 1, 2, 4, 8, 14, 22, 32). Nicotine (0.4 mg/kg, base) or saline was administered 5 min before each session. Estimates from the demand model were calculated between nicotine and saline administration conditions within subjects and changes in reinforcement value were assessed as differences in Q0, Pmax, Omax, and essential value. Nicotine administration increased operant responding across the entire range of reinforcement schedules tested, and uniformly affected model parameter estimates in a manner suggesting increased reinforcement value of the visual stimulus

A quantitative analysis of the reward-enhancing effects of nicotine using reinforcer demand

Reward enhancement by nicotine has been suggested as an important phenomenon contributing toward tobacco abuse and dependence. Reinforcement value is a multifaceted construct not fully represented by any single measure of response strength. The present study evaluated the changes in the reinforcement value of a visual stimulus in 16 male Sprague–Dawley rats using the reinforcer demand technique proposed by Hursh and Silberberg. The different parameters of the model have been shown to represent differing facets of reinforcement value, including intensity, perseverance, and sensitivity to changes in response cost. Rats lever-pressed for 1-min presentations of a compound visual stimulus over blocks of 10 sessions across a range of response requirements (fixed ratio 1, 2, 4, 8, 14, 22, 32). Nicotine (0.4 mg/kg, base) or saline was administered 5 min before each session. Estimates from the demand model were calculated between nicotine and saline administration conditions within subjects and changes in reinforcement value were assessed as differences in Q0, Pmax, Omax, and essential value. Nicotine administration increased operant responding across the entire range of reinforcement schedules tested, and uniformly affected model parameter estimates in a manner suggesting increased reinforcement value of the visual stimulus

Producer Cities and Consumer Cities: Using Production- and Consumption-Based Carbon Accounts to Guide Climate Action in China, the UK, and the US

Meeting the commitments made in the Paris Agreement on climate change will require different approaches in different countries. However, a common feature in many contexts relates to the continued and sometimes increasing significance of the carbon footprints of urban centres. These footprints consider both production or territorial (i.e. Scope 1 and 2) emissions, and consumption or extra-territorial (i.e. Scope 3) emissions. Although a growing number of cities have adopted targets for their production-based emissions, very few have even started to analyse or address their consumption-based emissions. This presents a potential challenge for urban policymaking if consumption emissions rise while production emissions fall, and for climate mitigation more broadly if emissions are effectively migrating to areas without carbon reduction targets or capabilities. To explore these issues, in this paper we analyse and compare production- and consumption-based emissions accounts for urban centres in China, the UK and the US. Results show that per-capita income and population density are strong predictors of consumption-based emissions levels, and consumption-based emissions appear to diminish but not decouple with higher per-capita incomes. In addition, results show that per-capita income is a predictor of net emissions - or the difference between production- and consumption-based accounts - suggesting that continuing increases in per capita income levels may drive the ‘leakage’ of urban emissions. These findings highlight a risk in placing too much faith in city-level climate strategies focused only on production-based emissions, and stress the importance of new city-level initiatives that focus on consumption-based emissions, especially in cities that are shifting from producer to consumer city status

Examining the Reinforcement-Enhancement Effects of Phencyclidine and Its Interactions with Nicotine on Lever-Pressing for a Visual Stimulus

Nicotine is a widely-abused drug, yet its primary reinforcing effect does not seem potent as other stimulants such as cocaine. Recent research on the contributing factors toward chronic use of nicotine-containing products has implicated the role of reinforcement-enhancing effects of nicotine. The present study investigates whether phencyclidine (PCP) may also possess a reinforcement-enhancement effect and how this may interact with the reinforcement-enhancement effect of nicotine. PCP was tested for two reasons: 1) it produces discrepant results on overall reward, similar to that seen with nicotine and 2) it may elucidate how other compounds may interact with the reinforcement-enhancement of nicotine. Adult male Sprague-Dawley rats were trained to lever press for brief visual stimulus presentations under fixed-ratio (FR) schedules of reinforcement and then were tested with nicotine (0.2 or 0.4 mg/kg) and/or PCP (2.0 mg/kg) over six increasing FR values. A selective increase in active lever-pressing for the visual stimulus with drug treatment was considered evidence of a reinforcement-enhancement effect. PCP and nicotine separately increased active lever pressing for a visual stimulus in a dose-dependent manner and across the different FR schedules. The addition of PCP to nicotine did not increase lever-pressing for the visual stimulus, possibly due to a ceiling effect. The effect of PCP may be driven largely by its locomotor stimulant effects, whereas the effect of nicotine was independent of locomotor stimulation. This dissociation emphasizes that distinct pharmacological properties contribute to the reinforcement-enhancement effects of substances

Examining the Reinforcement-Enhancement Effects of Phencyclidine and Its Interactions with Nicotine on Lever-Pressing for a Visual Stimulus

Nicotine is a widely-abused drug, yet its primary reinforcing effect does not seem potent as other stimulants such as cocaine. Recent research on the contributing factors toward chronic use of nicotine-containing products has implicated the role of reinforcement-enhancing effects of nicotine. The present study investigates whether phencyclidine (PCP) may also possess a reinforcement-enhancement effect and how this may interact with the reinforcement-enhancement effect of nicotine. PCP was tested for two reasons: 1) it produces discrepant results on overall reward, similar to that seen with nicotine and 2) it may elucidate how other compounds may interact with the reinforcement-enhancement of nicotine. Adult male Sprague-Dawley rats were trained to lever press for brief visual stimulus presentations under fixed-ratio (FR) schedules of reinforcement and then were tested with nicotine (0.2 or 0.4 mg/kg) and/or PCP (2.0 mg/kg) over six increasing FR values. A selective increase in active lever-pressing for the visual stimulus with drug treatment was considered evidence of a reinforcement-enhancement effect. PCP and nicotine separately increased active lever pressing for a visual stimulus in a dose-dependent manner and across the different FR schedules. The addition of PCP to nicotine did not increase lever-pressing for the visual stimulus, possibly due to a ceiling effect. The effect of PCP may be driven largely by its locomotor stimulant effects, whereas the effect of nicotine was independent of locomotor stimulation. This dissociation emphasizes that distinct pharmacological properties contribute to the reinforcement-enhancement effects of substances

Laboratory Notes From Behavioral Pharmacologists and Trainees: Considerations for the Discipline

In several laboratory meetings, we discussed the challenges that face trainees in behavioral pharmacology. Major concerns, such as a difficult funding climate and limited academic job prospects were discussed at first. However, we decided to concentrate on ways to meet these challenges; versus focusing on negatives and listing gripes. Within this more constructive framework, we identified the importance of broadening training to aligned areas to enhance the capacity of behavioral pharmacologists to collaborate in multidisciplinary teams. With increased breadth of training comes the concern for a balance that does not cheat trainees out of the depth of training also needed for success. We believe that behavioral pharmacologists trained in this manner will be ideally positioned to be leaders of these translational research teams. Related to the breadth and depth of training is the recent concerns over replicability and reproducibility of published research. Behavioral pharmacologists, with the rigors of training in behavioral analysis and experimental design, can be at the forefront of this conversation. This will be especially true if current training is reinforced with additional experience in the use of cutting-edge statistical tools that address the complex experimental designs and large data sets that emerge from modern multidisciplinary collaborations. Finally, communicating the import and potential societal impact of our research to legislators, other scientists, educators, school children, neighbors, and acquaintances is needed to ensure that our field thrives. In closing, the process of explicitly discussing the challenges and potential solutions with current trainees will enhance their mentoring and training

Laboratory Notes From Behavioral Pharmacologists and Trainees: Considerations for the Discipline

In several laboratory meetings, we discussed the challenges that face trainees in behavioral pharmacology. Major concerns, such as a difficult funding climate and limited academic job prospects were discussed at first. However, we decided to concentrate on ways to meet these challenges; versus focusing on negatives and listing gripes. Within this more constructive framework, we identified the importance of broadening training to aligned areas to enhance the capacity of behavioral pharmacologists to collaborate in multidisciplinary teams. With increased breadth of training comes the concern for a balance that does not cheat trainees out of the depth of training also needed for success. We believe that behavioral pharmacologists trained in this manner will be ideally positioned to be leaders of these translational research teams. Related to the breadth and depth of training is the recent concerns over replicability and reproducibility of published research. Behavioral pharmacologists, with the rigors of training in behavioral analysis and experimental design, can be at the forefront of this conversation. This will be especially true if current training is reinforced with additional experience in the use of cutting-edge statistical tools that address the complex experimental designs and large data sets that emerge from modern multidisciplinary collaborations. Finally, communicating the import and potential societal impact of our research to legislators, other scientists, educators, school children, neighbors, and acquaintances is needed to ensure that our field thrives. In closing, the process of explicitly discussing the challenges and potential solutions with current trainees will enhance their mentoring and training

Office-Based Educational Handout for Influenza Vaccination: A Randomized Controlled Trial

This is the author accepted manuscript. The final version is available from American Academy of Pediatrics via the DOI in this recordData sharing statement: De-identified individual participant data will not be made available.OBJECTIVES: To assess the impact of a parent educational intervention about influenza disease on child vaccine receipt. METHODS: A convenience sample of parents of children ≥6 months old with a visit at 2 New York City pediatric clinics between August 2016 and March 2017 were randomly assigned (1:1:1) to receive either usual care, an educational handout about influenza disease that was based on local data, or an educational handout about influenza disease that was based on national data. Parents received the handout in the waiting room before their visit. Primary outcomes were child influenza vaccine receipt on the day of the clinic visit and by the end of the season. A multivariable logistic regression was used to assess associations between intervention and vaccination, with adjustment for variables that were significantly different between arms. RESULTS: Parents who received an intervention (versus usual care) had greater odds of child influenza vaccine receipt by the end of the season (74.9% vs 65.4%; adjusted odds ratio 1.68; 95% confidence interval: 1.06-2.67) but not on the day of the clinic visit. Parents who received the national data handout (versus usual care) had greater odds of child influenza vaccine receipt on the day of the clinic visit (59.0% vs 52.6%; adjusted odds ratio 1.79; 95% confidence interval: 1.04-3.08) but not by the end of the season. CONCLUSIONS: Providing an educational intervention in the waiting room before a pediatric provider visit may help increase child influenza vaccine receipt.European CommissionNIH - Ruth L. Kirschstein National Research Service Awar