Does Sweet Taste Potentiate Nicotine Cue Reactivity?

Study Overview
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Brief Summary
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The investigators' aim is to test the prediction that sweet taste perception enhances the ability of nicotine to induce neural plastic changes in brain reward circuits to increase the saliency, liking and brain reactivity to the sight and vaporized flavor of electronic cigarettes (e-cigarettes).

Detailed Description
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Alternative tobacco products are becoming increasingly available in the US market and are promoted as potentially less deleterious compared to cigarettes. These products are increasing in usage as either a substitution for cigarette smoking or in addition to smoking. One particular appeal is that they often combine nicotine with sweet taste and flavors, which are themselves reinforcing. The primary goal of this project is to determine if sweet taste can potentiate the reinforcing properties of nicotine. Similar to nicotine, cues predicting the availability of carbohydrates can stimulate intake, even in the absence of hunger. The investigators have developed a novel flavor-nutrient conditioning paradigm to study the reinforcing properties of carbohydrates. Novel flavors are paired with 0 or 113 kcal carbohydrate and increases in flavor-cue reactivity (change in liking and brain response) when later sampled in the absence of the carbohydrate provide a measure of the reinforcing potency. For smokers, the aroma of tobacco is a potent cue that can promote smoking behavior. Using a modified version of our conditioning paradigm, our specific aim is to test the prediction that sweet taste perception enhances the ability of nicotine to induce neural plastic changes in brain reward circuits to increase the saliency, liking and brain reactivity to the sight and vaporized flavor of electronic cigarettes (e-cigarettes). Participants will smoke e-cigarettes that contain nicotine and an unsweetened vaporized flavor, nicotine and a sweet vaporized flavor or only a sweet vaporized flavor (no nicotine). The investigators predict that response in the nucleus accumbens and hypothalamus to the sight and vaporized flavor of the e-cigarette that was paired with nicotine and sweet taste will be greater than the responses to the sight and vaporized flavors associated with the other e-cigarettes. The investigators further predict that liking and wanting will increase more for the sight and vaporized flavor associated with both nicotine and sweet taste. This finding would provide strong evidence that sweet taste potentiates the reinforcement potency of nicotine and could therefore promote use.

Official Title
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Does Sweet Taste Potentiate Nicotine Cue Reactivity?

Conditions
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Healthy

Intervention / Treatment
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* Device: flavor and sweetener
* Device: flavor and nicotine
* Device: flavor, nicotine and sweetener
* Device: flavor


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: right handed non-daily smoker english speaking Exclusion Criteria: serious or unstable medical illness (e.g., cancer); past or current history of alcoholism or consistent drug use; current and history of major psychiatric illness as defined by the DSM-IV criteria including eating disorders, medications that affect alertness (e.g., barbiturates, benzodiazepines, chloral hydrate, haloperidol, lithium, carbamazepine, phenytoin, etc.) and any psychoactive drugs or anti-obesity agents; history of major head trauma with loss of consciousness; ongoing pregnancy; known taste or smell dysfunction; a diagnosis of diabetes; any known allergies or sensitivity, including to food, vapors or odors; pregnant or nursing women, history of metalworking, injury with shrapnel or metal slivers, and major surgery; history of pacemaker or neurostimulator implantation m) asthma, chronic obstructive pulmonary disease, bronchitis or any other lung disease.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Factorial Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: flavor and sweetener<br>E-cigarette with a novel flavor and sweetener added | Device: flavor and sweetener<br>* maltol added as sweetener to e-cigarette with flavor<br>|
| Experimental: flavor and nicotine<br>E-cigarette with a novel flavor and 12 mg nicotine added | Device: flavor and nicotine<br>* 12 mg of nicotine added to e-cigarette with flavor<br>|
| Experimental: flavor, nicotine and sweetener<br>E-cigarette with a novel flavor, sweetener, and 12 mg nicotine added | Device: flavor, nicotine and sweetener<br>* 12 mg nicotine and maltol (sweetener) added to e-cigarette with flavor<br>|
| Experimental: flavor<br>E-cigarette with a novel flavor: without a sweetener and 12 mg nicotine added | Device: flavor<br>* flavored e-cigarette stand alone without added nicotine and maltol (sweetener)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from Baseline on Rating: Liking | At baseline and 2 days post exposure, subjects will rate 'liking' using the general Labeled Hedonic Scale (LHS). The LHS is a vertical line scale with quasi-logarithmic spaced, with the label 'most imaginable dislike' in the bottom to 'most imaginable like' in the top, with the label 'neutral' in the middle (recoded to range of -100 to +100). | 2 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| percent signal change of nucleus accumbens from fMRI | brain response in nucleus accumbens and hypothalamus (in percent signal | on average 2 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Perception, brain response, nicotine, taste