Evidence map›Paper›PMID 27230546›Full record

ArticleAddiction biology2017

Brain CYP2B induction can decrease nicotine levels in the brain.

Kristine L P Garcia, Anh Dzung Lê, Rachel F Tyndale

Open access · greenAbstract read
In one paragraph

Article in Addiction biology, 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers.

0numbers the graph read from it
0cells of the map it votes in
3citing papers in PubMed
0.7field-weighted citation impact, top 26% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

3 citing papers in PubMed, 10 citations in OpenAlex.

  1. Review
  2. Article
  3. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

3 authors at 1 institution in 1 country.

Kristine L P GarciaDepartments of Pharmacology and Toxicology and Psychiatry, Toronto, Ontario, Canada.
Anh Dzung LêDepartments of Pharmacology and Toxicology and Psychiatry, Toronto, Ontario, Canada.
Rachel F TyndaleDepartments of Pharmacology and Toxicology and Psychiatry, Toronto, Ontario, Canada.
Centre for Addiction and Mental Health · CA

Funding

Reduced CYP2B6 metabolism influences smoking initiation and treatment response: iR21DA029160 · NIDA · CENTRE FOR ADDICTION AND MENTAL HEALTH · PI TYNDALE, RACHEL FYNVOLA · 2010 to 2011
$290k
NIDA NIH HHS R21 DA029160
6 · The paper itself

Abstract

Nicotine can be metabolized by the enzyme CYP2B; brain CYP2B is higher in rats and monkeys treated with nicotine, and in human smokers. A 7-day nicotine treatment increased CYP2B expression in rat brain but not liver, and decreased the behavioral response and brain levels (ex vivo) to the CYP2B substrate propofol. However, the effect of CYP2B induction on the time course and levels of circulating brain nicotine in vivo has not been demonstrated. Using brain microdialysis, nicotine levels following a subcutaneous nicotine injection were measured on day one and after a 7-day nicotine treatment. There was a significant time x treatment interaction (p = 0.01); peak nicotine levels (15-45 minutes post-injection) were lower after treatment (p = 0.04) consistent with CYP2B induction. Following a two-week washout period, brain nicotine levels increased to day one levels (p = 0.02), consistent with brain CYP2B levels returning to baseline. Brain pretreatment of the CYP2B inhibitor, C8-xanthate, increased brain nicotine levels acutely and after 7-day nicotine treatment, indicating the alterations in brain nicotine levels were due to changes in brain CYP2B activity. Plasma nicotine levels were not altered for any time or treatment sampled, confirming no effect on peripheral nicotine metabolism. These results demonstrate that chronic nicotine, by increasing brain CYP2B activity, reduces brain nicotine levels, which could alter nicotine's reinforcing effects. Higher brain CYP2B levels in smokers could lower brain nicotine levels; as this induction would occur following continued nicotine exposure it could increase withdrawal symptoms and contribute to sustaining smoking behavior.

Indexed as

Anesthetics, IntravenousAnimalsBrainCytochrome P450 Family 2LiverMaleMicrodialysisNicotineNicotinic AgonistsPropofolRatsRats, WistarReinforcement, PsychologyAnesthetics, IntravenousCytochrome P450 Family 2NicotineNicotinic AgonistsPropofolbrainCYP2Bmetabolismmicrodialysisnicotinerat

Identifiers

PMID27230546
PMCPMC5124551
OpenAlexW2409993441

What OpenQuestion holds

Textmetadata
LicenceTDM
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.