Smoking behaviors, including amount smoked, smoking cessation, and tobacco-related diseases, are altered by the rate of nicotine clearance. Nicotine clearance can be estimated using the nicotine metabolite ratio (NMR) (ratio of 3’hydroxycotinine/cotinine), but only in current smokers. Advancing the genomics of this highly heritable biomarker of CYP2A6, the main metabolic enzyme for nicotine, will also enable investigation of never- and former- smokers. We performed the largest genome-wide association study (GWAS) to date of the NMR in European ancestry current smokers (n=5185), found 1255 genome-wide significant variants, and replicated the chromosome 19 locus. Fine-mapping of chromosome 19 revealed 13 putatively causal variants, with nine of these being highly putatively causal and mapping to CYP2A6 , MAP3K10 , ADCK4 , and CYP2B6 . We also identified a putatively causal variant on chromosome 4 mapping to TMPRSS11E and demonstrated an association between TMPRSS11E variation and a UGT2B17 activity phenotype. Together the 14 putatively causal SNPs explained ~38% of NMR variation, a substantial increase from the ~20–30% previously explained. Our additional GWASs of nicotine intake biomarkers showed that cotinine and smoking intensity (cotinine/cigarettes per day (CPD)) shared chromosome 19 and 4 loci with the NMR, and that cotinine and a more accurate biomarker, cotinine+3’hydroxycotinine, shared a chromosome 15 locus near CHRNA5 with CPD and Pack-Years (i.e. cumulative exposure). Understanding the genetic factors influencing smoking-related traits facilitates epidemiological studies of smoking and disease, as well as assists in optimizing smoking cessation support, which in turn will reduce the enormous personal and societal costs associated with smoking.

The Pharmacogene Variation Consortium (PharmVar) catalogs star (*) allele nomenclature for the polymorphic human CYP2B6 gene. Genetic variation within the CYP2B6 gene locus impacts the metabolism or bioactivation of clinically important drugs. Of particular importance are efficacy and safety concerns regarding: efavirenz, which is used for the treatment of HIV type‐1 infection; methadone, a mainstay in the treatment of opioid use disorder and as an analgesic; ketamine, used as an antidepressant and analgesic; and bupropion, which is prescribed to treat depression and for smoking cessation. This GeneFocus provides a comprehensive overview and summary of CYP2B6 and describes how haplotype information catalogued by PharmVar is utilized by the Pharmacogenomics Knowledgebase (PharmGKB) and the Clinical Pharmacogenetics Implementation Consortium (CPIC).

Background Black-white differences in smoking abstinence are not well understood. This trial sought to confirm previously reported differences in quitting between blacks and whites and to identify factors underlying this difference. Methods During enrollment, 224 black and 225 white low-income smokers were stratified on race and within race on age and sex to ensure balance on these factors known to impact abstinence. The intervention included varenicline for 12 weeks and six guideline-based smoking cessation counseling sessions. The primary endpoint was cotinine-verified 7-day point prevalence smoking abstinence at week 26. A priori socioeconomic, smoking, treatment process (eg, treatment utilization, side effects, withdrawal relief), psychosocial, and biological factors were assessed to investigate race differences in abstinence. Unadjusted odds ratios (OR) were used to compare abstinence between blacks and whites. Adjusted odds ratios from logistic regression models were used to examine predictors of abstinence. All statistical tests were two-sided. Results Blacks were less likely to achieve abstinence at week 26 (14.3% vs 24.4%, OR = 0.51, 95% confidence interval [CI] = 0.32 to 0.83, P = .007). Utilizing best subsets logistic regression, five factors associated with race jointly predicted abstinence: home ownership (yes/no, OR = 3.03, 95% CI = 1.72 to 5.35, P < .001), study visits completed (range = 0–6, OR = 2.81, 95% CI = 1.88 to 4.20, P < .001), income (household member/$1000, OR = 1.03, 95% CI = 1.01 to 1.06, P = .02), plasma cotinine (per 1 ng/mL, OR = 0.997, 95% CI = 0.994 to 0.999, P = .002), and neighborhood problems (range = 10–30, OR = 0.88, 95% CI = 0.81 to 0.96, P = .003). Conclusions The race difference in abstinence was fully explained by lack of home ownership, lower income, greater neighborhood problems, higher baseline cotinine, and higher visit completion, which were disproportionately represented among blacks. Findings illuminate factors that make it harder for blacks in the United States to quit smoking relative to whites and provide important areas for future studies to reduce tobacco-related health disparities.

Depression and anxiety are more common among females than males and represent a leading cause of diseaserelated disability in women. Since the dopamine D1-D2 heteromer is involved in depression-and anxiety-like behavior, the possibility that the receptor complex may have a role in mediating sex differences in such behaviors and related biochemical signaling was explored. In non-human primate caudate nucleus and in rat striatum, females expressed higher density of D1-D2 heteromer complexes and a greater number of D1-D2 expressing neurons compared to males. In rat, the sex difference in D1-D2 expression levels occurred even though D1 receptor expression was lower in female than in male with no difference in D2 receptor expression. In behavioral tests, female rats showed faster latency to depressive-like behavior and a greater susceptibility to the pro-depressive and anxiogenic-like effects of D1-D2 heteromer activation by low doses of SKF 83959, all of which were ameliorated by the selective heteromer disrupting peptide, TAT-D1. The sex difference observed in the anxiety test correlated with differences in low-frequency delta and theta oscillations in the nucleus accumbens. Analysis of signaling pathways revealed that the sex difference in D1-D2 heteromer expression led to differences in basal and heteromer-stimulated activities of two important signaling pathways, BDNF/TrkB and Akt/GSK3/β-catenin. These results suggest that the higher D1-D2 heteromer expression in female may significantly increase predisposition to depressive-like and anxiety-like behavior in female animals.

This article is available online at http://dmd.aspetjournals.org ABSTRACT:Buprenorphine is a thebaine derivative used in the treatment of heroin and other opiate addictions. In this study, the selective probe reactions for each of the major hepatic cytochromes P450 (P450s) were used to evaluate the effect of buprenorphine and its main metabolite norbuprenorphine on the activity of these P450s.

We have investigated the GABAA receptor mRNA composition in 13 cell lines, using 13 subunit-specific oligo-primers (alpha 1-6, beta 1-3, gamma 1-3, and delta) and reverse transcriptase PCR amplification. Cell lines (B35, B65, B103, B104, RINm5F, Rat1, PC12, C6, C17, C27, beta TC3, NB41A3, AtT-20), derived from diverse tissue origins, were investigated in order to identify homogeneous cellular sources with distinctive GABAA receptor subunits. Fifteen GABAA receptor subunits have been cloned from mammalian tissue (those listed above plus the retinal subunits rho 1 and rho 2). This multiplicity of GABAA receptor subunits underlies the diverse pharmacology of the GABAA receptor. Attempts to understand the regulation and pharmacology of individual subunits and of the heterooligomeric receptor combinations have been impeded by a lack of pure populations of cells expressing GABAA receptor subunits. Permanent cell lines provide such a resource. Each GABAA receptor subunit mRNA, alpha 1-5, beta 1-3, gamma 1-3, and delta, was detected in at least one cell line. All cell lines examined contained detectable levels of at least one GABAA receptor subunit mRNA. Each cell line contained distinctive combinations of subunit mRNAs. None of the cell lines examined contained detectable amounts of alpha 6 mRNA. These cell lines, which transcribe GABAA receptor subunit mRNAs, provide useful cellular sources for transcriptional and pharmacological studies. Our data also suggest that endogenous GABAA receptor subunit mRNAs may be present in cells that are routinely used for transfection studies, and that this expression might confound interpretation of the studies. In the following companion article, we have looked for functional GABAA receptor Cl- ion channels in these cell lines, using the patch-clamp technique (Hales and Tyndale, 1994).

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Introduction: The simple phenol hydroxytyrosol (OHTyr) has been associated with the beneficial health effects of extra virgin olive oil. Pre-clinical studies have identified Tyr hydroxylation, mediated by cytochrome P450 isoforms CYP2A6 and CYP2D6, as an additional source of OHTyr. Aim: We aimed to (i) confirm Tyr to OHTyr bioconversion in vivo in humans, (ii) to assess the cardiovascular benefits of this bioconversion, and (iii) determine their interaction with a polygenic activity score (PAS) from CYP2A6 and CYP2D6 genotypes. Methods: Randomized, crossover, controlled study. Individuals at cardiovascular risk (n=33) received: white wine (WW) (females 1, males 2 standard drinks/day), WW plus Tyr capsules (WW+Tyr) (25mg Tyr capsule, one per WW drink), and water (control) ad libitum. Participants were classified by a PAS as low versus normal activity metabolizers. Results: OHTyr recovery following WW+Tyr was higher than after other interventions (P<0.05). Low PAS individuals had lower OHTyr/Tyr ratios compared to individuals with normal PAS. WW+Tyr improved endothelial function, increased plasma HDLcholesterol and antithrombin IIII, and decreased plasma homocysteine, endothelin 1, and CD40L, P65/RELA, and CFH gene expression in peripheral blood mononuclear cells (p<0.05). Combining Tyr capsule(s) with WW abolished the increase in iNOS, eNOS, VEGFA, and CHF expressions promoted by WW (p<0.05). Conclusions: Tyr, and its partial biotransformation into OHTyr, promoted cardiovascular health-related benefits in humans after dietary doses of Tyr. The study 5 design allowed the health effects of individual phenols to be singled out from the dietary matrix in which they are naturally found.