Biomedical subjects

Richard E Olmstead

Publications and source records attributed to Richard E Olmstead.

8 recordsLinked to original sources

PubMed2007

Neural substrates of resisting craving during cigarette cue exposure.

BACKGROUND: In cigarette smokers, the most commonly reported areas of brain activation during visual cigarette cue exposure are the prefrontal, anterior cingulate, and visual cortices. We sought to determine changes in brain activity in response to cigarette cues when smokers actively resist craving. METHODS: Forty-two tobacco-dependent smokers underwent functional magnetic resonance imaging, during which they were presented with videotaped cues. Three cue presentation conditions were tested: cigarette cues with subjects allowing themselves to crave (cigarette cue crave), cigarette cues with the instruction to resist craving (cigarette cue resist), and matched neutral cues. RESULTS: Activation was found in the cigarette cue resist (compared with the cigarette cue crave) condition in the left dorsal anterior cingulate cortex (ACC), posterior cingulate cortex (PCC), and precuneus. Lower magnetic resonance signal for the cigarette cue resist condition was found in the cuneus bilaterally, left lateral occipital gyrus, and right postcentral gyrus. These relative activations and deactivations were more robust when the cigarette cue resist condition was compared with the neutral cue condition. CONCLUSIONS: Suppressing craving during cigarette cue exposure involves activation of limbic (and related) brain regions and deactivation of primary sensory and motor cortices.

Adult↗

PubMed2006

Preferences among four combination nicotine treatments.

RATIONALE: Acute nicotine replacement treatments (NRTs) are disliked or misused, leading to insufficient nicotine intake and poor outcome. Patches provide steady nicotine but are slow and passive. Combining systems may improve efficacy with acute NRTs tailored for compliance. OBJECTIVE: To test initial reactions to and use preferences among combinations of NRTs. MATERIALS AND METHODS: Smokers (n=27) tested four combination NRTs in a 5-day crossover trial: 2/4-mg gum + 15-mg patch (G/P), 2/4-mg lozenges + 15-mg patch (L/P), inhaler + 15-mg patch (I/P), and 10 mg + 15-mg patches (P/P). Subjects rated an NRT combination each day after 5-6 h of use and ranked among the NRTs after testing all treatments. RESULTS: Double-patches (P/P) were ranked highest for "ease of use", "safety", and "use in public". However, for "help to quit", 70% preferred some form of acute-patch combination (A/P) compared to 30% choosing P/P. For "use under stress" (an immediate need), 93% preferred A/P systems compared to 7% choosing P/P. L/P ranked lowest for "ease of use", I/P and L/P were lowest on "safety", and I/P ranked lowest for "use in public". Expectations of NRTs changed with test experience for patches (better) and lozenges (worse). CONCLUSIONS: In brief testing, all combinations were acceptable. P/P was favored for ease, safety, and public use, but a majority chose A/P systems for help in quitting and use under stress. Combined use is viable and needs to be made known and accessible to smokers.

Administration, Cutaneous↗

PubMed2006

Gene variants of brain dopamine pathways and smoking-induced dopamine release in the ventral caudate/nucleus accumbens.

CONTEXT: Preclinical studies demonstrate that nicotine administration leads to dopamine release in the ventral striatum. However, human studies reveal considerable interindividual variability in the extent of smoking-induced dopamine release. OBJECTIVE: To determine whether common gene variants of the brain dopamine pathway explain this observed phenotypic variability in humans. DESIGN: Blood samples were drawn to determine gene variants of dopamine system components, and positron emission tomography scanning with the radiotracer raclopride labeled with radioactive carbon (11C) was performed to measure smoking-induced dopamine release. SETTING: Academic brain imaging center. PARTICIPANTS: Forty-five tobacco-dependent smokers. INTERVENTIONS: Subjects either smoked a cigarette (n = 35) or did not smoke (n = 10) during positron emission tomography scanning. MAIN OUTCOME MEASURES: Gene variants of dopamine system components (the dopamine transporter variable nucleotide tandem repeat, D2 receptor Taq A1/A2, D4 receptor variable nucleotide tandem repeat, and catechol-O-methyltransferase Val158Met polymorphisms) and change in [11C]raclopride binding potential in the ventral caudate/nucleus accumbens on positron emission tomography scans. RESULTS: For subjects who smoked during scanning, those with at least one 9 allele of the dopamine transporter variable nucleotide tandem repeat, fewer than 7 repeats of the D4 variable nucleotide tandem repeat, and the Val/Val catechol-O-methyltransferase genotype had greater decreases in binding potential (an indirect measure of dopamine release) with smoking than those with the alternate genotypes. An overall decrease in ventral caudate/nucleus accumbens binding potential in those who smoked compared with those who did not smoke was also found but was smaller in magnitude than previously reported. CONCLUSIONS: Smokers with genes associated with low resting dopamine tone have greater smoking-induced (phasic) dopamine release than those with alternate genotypes. These findings suggest that dopamine system genotype variabilities explain a significant proportion of the interindividual variability in smoking-induced dopamine release and indicate that smoking-induced dopamine release has a genetic predisposition.

Adult↗

PubMed2006

Cigarette smoking saturates brain alpha 4 beta 2 nicotinic acetylcholine receptors.

CONTEXT: 2-[18F]fluoro-3-(2(S)-azetidinylmethoxy) pyridine (2-F-A-85380, abbreviated as 2-FA) is a recently developed radioligand that allows for visualization of brain alpha 4 beta 2* nicotinic acetylcholine receptors (nAChRs) with positron emission tomography (PET) scanning in humans. OBJECTIVE: To determine the effect of cigarette smoking on alpha 4 beta 2* nAChR occupancy in tobacco-dependent smokers. DESIGN: Fourteen 2-FA PET scanning sessions were performed. During the PET scanning sessions, subjects smoked 1 of 5 amounts (none, 1 puff, 3 puffs, 1 full cigarette, or to satiety [2(1/2) to 3 cigarettes]). SETTING: Academic brain imaging center. PARTICIPANTS: Eleven tobacco-dependent smokers (paid volunteers). Main Outcome Measure Dose-dependent effect of smoking on occupancy of alpha 4 beta 2* nAChRs, as measured with 2-FA and PET in nAChR-rich brain regions. RESULTS: Smoking 0.13 (1 to 2 puffs) of a cigarette resulted in 50% occupancy of alpha 4 beta 2* nAChRs for 3.1 hours after smoking. Smoking a full cigarette (or more) resulted in more than 88% receptor occupancy and was accompanied by a reduction in cigarette craving. A venous plasma nicotine concentration of 0.87 ng/mL (roughly 1/25th of the level achieved in typical daily smokers) was associated with 50% occupancy of alpha 4 beta 2* nAChRs. CONCLUSIONS: Cigarette smoking in amounts used by typical daily smokers leads to nearly complete occupancy of alpha 4 beta 2* nAChRs, indicating that tobacco-dependent smokers maintain alpha 4 beta 2* nAChR saturation throughout the day. Because prolonged binding of nicotine to alpha 4 beta 2* nAChRs is associated with desensitization of these receptors, the extent of receptor occupancy found herein suggests that smoking may lead to withdrawal alleviation by maintaining nAChRs in the desensitized state.

Adult↗

PubMed2005

Comparison of three nicotine treatments: initial reactions and preferences with guided use.

RATIONALE: Misuse or dislike of nicotine replacement treatments (NRTs) undermines their effectiveness. Brief testing among NRTs could allow tailoring by preference to improve outcome. OBJECTIVE: To test initial reactions/preferences to NRTs in a single session crossover design with guided use. METHODS: Smokers were offered two doses of three NRTs: gum (2 and 4 mg), inhaler, and nasal spray (NNS) in a 5-h test with proper use enforced. Subjects rated each NRT and ranked among NRTs on use variables and preferences. RESULTS: Gum was ranked over inhaler and NNS for "ease of use," "safety" and "prefer in public." Four-milligram gum was rated higher than 2 mg on several variables. With experience, "ease of use" and "liking" improved for gum. Both inhaler and NNS ranked low on considering "use >3 months" vs gum. Dislike of NRT was reflected in refusal of second doses. For those testing all doses (n=9), inhaler ranked last on "relief of withdrawal," "choose under stress," and "choice to help quit." Craving and withdrawal were relieved over time with any NRT use. CONCLUSIONS: Sampling of treatments can identify reactions key to initial compliance with these NRTs.

Adult↗

PubMed2004

Smoking-induced ventral striatum dopamine release.

OBJECTIVE: Substantial evidence from animal models demonstrates that dopamine release in the ventral striatum underlies the reinforcing properties of nicotine. The authors used [(11)C]raclopride bolus-plus-continuous-infusion positron emission tomography (PET) to determine smoking-induced ventral striatum dopamine release in humans. METHOD: Twenty nicotine-dependent smokers (who smoked > or =15 cigarettes/day) underwent a [(11)C]raclopride bolus-plus-continuous-infusion PET session. During the session, subjects had a 10-minute break outside the PET apparatus during which 10 subjects smoked a cigarette and 10 did not smoke (as a control condition). RESULTS: The group that smoked had greater reductions in [(11)C]raclopride binding potential in ventral striatum regions of interest than the group that did not smoke, particularly in the left ventral caudate/nucleus accumbens and left ventral putamen (range for smoking group=-25.9% to -36.6% reduction). Significant correlations were found between change from before to after the smoking break in craving ratings and change from before to after the break in binding potential for these two regions. CONCLUSIONS: Nicotine-dependent subjects who smoked during a break in PET scanning had greater reductions in [(11)C]raclopride binding potential (an indirect measure of dopamine release) than nicotine-dependent subjects who did not smoke. The magnitude of binding potential changes was comparable to that found in studies that used similar methods to examine the effects of other addictive drugs.

Adult↗

PubMed2002

Modulating tobacco smoking rates by dopaminergic stimulation and blockade.

This study was designed to demonstrate that dopaminergic stimulation would result in decreased smoking behavior and nicotine intake, whereas dopaminergic blockade would result in increased smoking behavior and nicotine intake, in the same subjects. In prior human studies, a dopaminergic antagonist, haloperidol, increased smoking and/or nicotine intake, and a dopamine agonist, bromocriptine, decreased smoking. The smoking behavior of 20 heavy smokers was observed on two separate visits in a randomized, double-blind, repeated-measures-within-subject design. In the drug-reversal design, either bromocriptine (2.5 mg) or haloperidol (2.0 mg) was administered at each 5-h session, during which subjects smoked their own cigarettes ad libitum. Smoking topography was measured using a thermistor flow detector apparatus. Subjects smoked their cigarettes faster (p<0.05) and total puffing time was greater (p<0.05) with haloperidol than with bromocriptine. There was a trend for both a shorter latency to smoke (p<0.10, one-tailed) during time of expected peak drug concentration and for a shorter inter-cigarette interval with haloperidol than with bromocriptine (p<0.10, one-tailed). Shiffman-Jarvik Withdrawal Scale craving subscale scores increased significantly more with haloperidol than with bromocriptine (p<0.05). Mean Profile of Mood States (POMS) scores differed significantly for only one subscale (Confusion: bromocriptine>haloperidol; p<0.05). These data support the hypothesis that nicotine mediates reinforcement from smoking via dopamine, and that smoking behavior can be manipulated within the same subjects in opposite directions by alternately stimulating and blocking dopamine.

Adolescent↗

PubMedDate not supplied

Comparative testing of 5 nicotine systems: initial use and preferences.

OBJECTIVE: To test initial reactions to 5 nicotine treatments (NRTs: 2 and 4 mg gum, inhaler, nasal spray, tablet) in a crossover study (n=41). METHODS: Subjects used each medication on arising (1/2 day) and resumed smoking each afternoon. Subjects rated (individually) and ranked (comparatively) treatments on use, reinforcement, withdrawal, craving, and preferences. RESULTS: Overall preferences: inhaler (49%), 4 mg gum (24%), 2 mg gum (10%), 2 mg tablet (10%), nasal spray (7%). Overall results were consistent with ratings and rankings of individual characteristics of drugs. CONCLUSION: Subjects had varied reactions to NRTs that may affect initiation of cessation.

Chewing Gum↗