Catechol-O-methyltransferase activity in individuals with substance use disorders: a case control study.

BACKGROUND: Impulsivity and substance use disorders (SUD) have been both associated with changes in dopaminergic processes. In this study, we intended to evaluate the dopaminergic function in imprisoned SUD offenders through the determination of s-COMT activity. METHODS: The study included 46 male individuals from a Portuguese penal institution. The participants were assessed through a battery of standardised instruments: Psychopathy Checklist-Revised (PCL-R), Barratt Impulsivity Scale Version 11 (BIS-11), and the European version of the Addiction Severity Index (EuropASI). In addition, s-COMT erythrocyte activity was evaluated. RESULTS: Overall, 73.9% (n = 34) of the individuals had Antisocial personality disorder (ASPD) and 58.7% (n = 27) presented SUD. We evidenced, for the first time, that, in individuals with SUD, s-COMT activity was correlated with the severity of drug dependence (EuropASI) (p = 0.009), and with BIS-11 factors self-control (p < 0.0001) and non-planning (p = 0.002). CONCLUSIONS: This study opens new perspectives regarding the pharmacological intervention on substance dependence through the interference on dopamine pathways.

D3 dopamine receptors and a missense mutation of fatty acid amide hydrolase linked in mouse and men: implication for addiction.

The endocannabinoid and dopaminergic systems have independently been implicated in substance use disorder and obesity. We investigated a potential interaction between genetically inherited variation in fatty acid amide hydrolase (FAAH, C385A), which metabolizes the cannabis-like endocannabinoid anandamide, and dopaminergic system, measured by dopamine receptor levels and mRNA. Binding of the dopamine D3 preferring probe [C-11]-(+)-PHNO was measured with positron emission tomography (PET) in 79 human subjects genotyped for the FAAH C385A polymorphism (36/79 AC + AA). Autoradiography with [H-3]-(+)-PHNO and in situ hybridization with a D3-specific S-35 riboprobe were carried out in 30 knock-in mice with the FAAH C385A polymorphism (20/30 AC + AA). We found that the FAAH genetic variant C385A was associated with significantly higher (+)-PHNO binding in both humans and in knock-in mice, and this effect was restricted to D3 selective brain regions (limbic striatum, globus pallidus, and ventral pallidum (9-14%; p < 0.04) in humans and Islands of Calleja (28%; p = 0.036) in mice). In situ hybridization with a D3-specific S-35 riboprobe in FAAH knock-in C385A mice confirmed significantly increased D3 receptor mRNA across examined regions (7-44%; p < 0.02). The association of reduced FAAH function with higher dopamine D3 receptors in human and mouse brain provide a mechanistic link between two brain systems that have been implicated in addiction-risk. This may explain the greater vulnerability for addiction and obesity in individuals with C385A genetic variant and by extension, suggest that a D3 antagonism strategy in substance use disorders should consider FAAH C385A polymorphism.

Associations between experimental substance use, faah-gene variations, impulsivity and sensation seeking / Asociaciones entre el uso experimental de sustancias, variaciones del gen FAAH, impulsividad y búsqueda de sensaciones

Background: Experimental substance use among young people is related to individual factors including personality traits such as impulsivity and sensation seeking, and genetic variations such as single nucleotide polymorphisms (SNPs) in the fatty acid amide hydrolase (FAAH) gene. The objective of this study is to analyze the relationship between these three sets of variables. Methods: Volunteer undergraduate students (N = 861, 76% female, M = 20.7 years) completed an ad hoc questionnaire on variables related to their consumption of alcohol, tobacco, cannabis, synthetic drugs and cocaine. In addition, 591 of them completed the Barratt Impulsiveness Scale-11 (BIS-11) and the Sensation Seeking Scale-V (SSS-V). All participants were genotyped in FAAH C385A SNP and its proxy variant rs12075550. Results: Consistent with previous data, both impulsivity and sensation seeking were associated with most of the variables related to experimental substance use. In addition, we found the first evidence of an association between the rs12075550 SNP and some of these consumption phenotypes. However, no significant association was found between either of the two SNPs and impulsivity or sensation seeking. Conclusions: The results highlight the importance of considering both personality and genetic differences, together with contextual factors, in the analysis of substance use

Antecedentes: el uso experimental de sustancias en los jóvenes está relacionada con factores individuales que incluyen rasgos de personalidad, como impulsividad o búsqueda de sensaciones, y variaciones genéticas, como polimorfismos de un solo nucleótido (SNPs) del gen amida hidrolasa de ácidos grasos (FAAH). El objetivo de este estudio es analizar la relación entre estos tres conjuntos de variables. Método: estudiantes universitarios voluntarios (N = 861, 76% mujeres, M = 20,7 años) rellenaron un cuestionario ad hoc de variables relacionadas con el consumo de alcohol, tabaco, cannabis, drogas sintéticas y cocaína. Además, 591 de ellos rellenaron las escalas BIS-11 y SSS-V. Se genotipó a todos ellos en SNP FAAH C385A y su variante proxy rs12075550. Resultados: como se esperaba, la impulsividad y la búsqueda de sensaciones estuvieron asociadas con la mayor parte de las variables relativas al uso experimental de sustancias. Además, encontramos por primera vez evidencia de una asociación entre rs12075550 y algunos de estos fenotipos de consumo. Sin embargo, no encontramos asociaciones significativas entre SNPs e impulsividad o búsqueda de sensaciones. Conclusiones: los resultados resaltan la importancia de tener en cuenta las diferencias genéticas y las de personalidad, junto con los factores contextuales, al analizar el uso de sustancias

Associations between experimental substance use, FAAH-gene variations, impulsivity and sensation seeking.

BACKGROUND: Experimental substance use among young people is related to individual factors including personality traits such as impulsivity and sensation seeking, and genetic variations such as single nucleotide polymorphisms (SNPs) in the fatty acid amide hydrolase (FAAH) gene. The objective of this study is to analyze the relationship between these three sets of variables. METHODS: Volunteer undergraduate students (N = 861, 76% female, M = 20.7 years) completed an ad hoc questionnaire on variables related to their consumption of alcohol, tobacco, cannabis, synthetic drugs and cocaine. In addition, 591 of them completed the Barratt Impulsiveness Scale-11 (BIS-11) and the Sensation Seeking Scale-V (SSS-V). All participants were genotyped in FAAH C385A SNP and its proxy variant rs12075550. RESULTS: Consistent with previous data, both impulsivity and sensation seeking were associated with most of the variables related to experimental substance use. In addition, we found the first evidence of an association between the rs12075550 SNP and some of these consumption phenotypes. However, no significant association was found between either of the two SNPs and impulsivity or sensation seeking. CONCLUSIONS: The results highlight the importance of considering both personality and genetic differences, together with contextual factors, in the analysis of substance use.

Novel prodrug PRX-P4-003, selectively activated by gut enzymes, may reduce the risk of iatrogenic addiction and abuse.

OBJECTIVES: Prescription stimulants are vulnerable to oral and parenteral abuse. Intravenous forms of abuse may be most detrimental due to an enhanced risk of dependence, overdose, and infectious diseases. Our objective was to discover an orally active prodrug of a stimulant that would not be easily converted to its parent when injected, thus hindering intravenous abuse. METHODS: Following an initial analysis of stimulant structures, the fencamfamine isomer [(-)-FCF; (N-ethyl-3-phenylbicyclo[2.2.1]heptan-2-amine)] was chosen as a parent drug due to its favorable biochemical properties. Subsequently, PRX-P4-003 {(-)-N-(Octadecanoyloxymethoxycarbonyl)-N-ethyl-3-phenylbicyclo[2.2.1]heptan-2-amine} qualified for further development. Experimental testing of PRX-P4-003 included radioligand binding assays, stability studies, and rodent pharmacokinetic and locomotor assays. RESULTS: Prodrug PRX-P4-003 is a pharmacologically inactive, hydrophobic compound, whereas its parent (-)-FCF is a dopamine reuptake inhibitor with weaker effects on norepinephrine reuptake (Ki = 0.07 and 0.80 µM, respectively). PRX-P4-003 is metabolized to (-)-FCF in simulated intestinal fluid (with pancreatin) but not in simulated gastric fluid (with pepsin). Finally, PRX-P4-003 shows a significant oral but no intravenous increase in locomotion, correlating with its pharmacokinetics by these different routes of administration. CONCLUSIONS: PRX-P4-003 is a novel prodrug stimulant enzymatically activated in the gut. Our data suggest a pancreatic, lipase-based mechanism of activation and as only 1% of this enzyme is found in the systemic circulation, PRX-P4-003 is unlikely to be bioactive if injected intravenously. Enzymatic release of (-)-FCF is needed prior to its systemic absorption, which may discourage oral abuse (e.g., by chewing). PRX-P4-003 is being developed for apathy in Alzheimer's disease and binge eating disorder.

Analysis of Elevated Levels of Nandrolone Decanoate Induced Cytochrome- P450 Alterations in Mice.

BACKGROUND: Frequent recreational use of Anabolic Androgenic Steroids (AAS) is an instance of substance abuse which mimics the status of a natural hormone and upon prolonged exposure may lead to adverse drug reactions. These adverse drug reactions proceed in a manner so as to alter the normal metabolism of an enzyme mediated pathway such as the Cytochrome P450 (CYP) family of enzymes. OBJECTIVE: The present study was conducted to investigate the impact of overuse of Nandrolone Decanoate (ND), an AAS, upon CYP enzyme activity and a CYP gene, belonging to CYP1 family. METHODS: The study was carried out using normal and ND treated male albino mice. Genetic analysis was conducted using normalized and treated cDNA and reverse transcriptase polymerase chain reaction based assays. For enzyme assay, 0.1ml of 25 mg ND was administered to the animals twice a week for a period of 90 days. Genetic analysis was carried out with the same dose but administered for a period of 360 days. RESULTS: CYP enzyme activity increased significantly (p<0.01) in the ND treated group of animals compared to that in the normal group. However, no noticeable alteration was observed at the molecular level. CONCLUSION: From the present study it could be inferred that, at elevated doses, ND has the potential to alter hepatic CYP enzyme activity without any modification in the CYP gene. This could be due to a possible adaptive response of the living system to such drugs.

What is the contribution of human FMO3 in the N-oxygenation of selected therapeutic drugs and drugs of abuse?

Little is known about the role of flavin-containing monooxygenases (FMOs) in the metabolism of xenobiotics. FMO3 is the isoform in adult human liver with the highest impact on drug metabolism. The aim of the presented study was to elucidate the contribution of human FMO3 to the N-oxygenation of selected therapeutic drugs and drugs of abuse (DOAs). Its contribution to the in vivo hepatic net clearance of the N-oxygenation products was calculated by application of an extended relative activity factor (RAF) approach to differentiate from contribution of cytochrome P450 (CYP) isoforms. FMO3 and CYP substrates were identified using pooled human liver microsomes after heat inactivation and chemical inhibition, or single enzyme incubations. Kinetic parameters were subsequently determined using recombinant human enzymes and mass spectrometric analysis via authentic reference standards or simple peak areas of the products divided by those of the internal standard. FMO3 was identified as enzyme mainly responsible for the formation of N,N-diallyltryptamine N-oxide and methamphetamine hydroxylamine (>80% contribution for both). A contribution of 50 and 30% was calculated for the formation of N,N-dimethyltryptamine N-oxide and methoxypiperamide N-oxide, respectively. However, FMO3 contributed with less than 5% to the formation of 3-bromomethcathinone hydroxylamine, amitriptyline N-oxide, and clozapine N-oxide. There was no significant difference in the contributions when using calibrations with reference metabolite standards or peak area ratio calculations. The successful application of a modified RAF approach including FMO3 proved the importance of FMO3 in the N-oxygenation of DOAs in human metabolism.

The role of MAO in personality and drug use.

Monoamine oxidases, both MAO-A and MAO-B, have been implicated in personality traits and complex behaviour, including drug use. Findings supporting the involvement of MAO-A and MAO-B in shaping personality and in the development of strategies of making behavioural choices come from a variety of studies that have examined either prevalence of gene variants in clinical groups or population-derived samples, estimates of enzyme activity in blood or, by positron emission tomography, in the brain and, most recently, measurement of methylation of the gene. Most of the studies converge in associating MAO-A and MAO-B with impulsive, aggressive or antisocial personality traits or behaviours, including alcohol-related problems, and for MAO-A available evidence strongly supports interaction with adverse environmental exposures in childhood. What is known about genotype effects, and on expression and activity of the enzyme in the brain and in blood has not yet been possible to unite into a mechanistic model of the role of monoamine systems, but the reason for this low degree of generalization is likely caused by the cross-sectional nature of investigation that has not incorporated the developmental effects of MAO-s in critical time windows, including the foetal period. The "risk variants" of both MAO-s appear to increase behavioural plasticity, as supportive environments may particularly well enhance the hidden potential of their carriers. Importantly, male and female brain and behaviours have been found very different with regard to MAO×life events interaction. Future studies need to take into consideration these developmental aspects and sex/gender, as well as to specify the role of different types of environmental factors.

CaM Kinases: From Memories to Addiction.

Drug addiction is a major psychiatric disorder with a neurobiological basis that is still insufficiently understood. Initially, non-addicted, controlled drug consumption and drug instrumentalization are established. They comprise highly systematic behaviours acquired by learning and the establishment of drug memories. Ca(2+)/calmodulin-dependent protein kinases (CaMKs) are important Ca(2+) sensors translating glutamatergic activation into synaptic plasticity during learning and memory formation. Here we review the role of CaMKs in the establishment of drug-related behaviours in animal models and in humans. Converging evidence now shows that CaMKs are a crucial mechanism of how addictive drugs induce synaptic plasticity and establish various types of drug memories. Thereby, CaMKs are not only molecular relays for glutamatergic activity but they also directly control dopaminergic and serotonergic activity in the mesolimbic reward system. They can now be considered as major molecular pathways translating normal memory formation into establishment of drug memories and possibly transition to drug addiction.

Regulation of cell differentiation and function by the euchromatin histone methyltranserfases G9a and GLP.

The euchromatin histone methyltransferases (EHMTs) are an evolutionarily conserved protein family that are known for their ability to dimethylate histone 3 at lysine 9 in euchromatic regions of the genome. In mammals there are two EHMT proteins, G9a, encoded by EHMT2, and GLP, encoded by EHMT1. EHMTs have diverse roles in the differentiation of different tissues and cell types and are involved in adult-specific processes like memory, drug addiction, and immune response. This review discusses recent findings from rodent and Drosophila models that are beginning to reveal the broad biological role and complex mechanistic functioning of EHMT proteins.

Effects of tramadol, clonazepam, and their combination on brain mitochondrial complexes.

The present study is an unsubstantiated qualitative assessment of the abused drugs-tramadol and clonazepam. The aim of this study is to evaluate whether the effects of tramadol, clonazepam, and their combination on mitochondrial electron transport chain (ETC) complexes were influential at therapeutic or at progressively increasing doses. The study comprised of a total of 70 healthy male rats, aged 3 months. According to the drug intake regimen, animals were divided into seven groups: control, tramadol therapeutic, clonazepam therapeutic, combination therapeutic, tramadol abuse, clonazepam abuse, and combination abuse group. At the end of the experiment, brain mitochondrial ETC complexes (I, II, III, and IV) were evaluated. Histopathological examinations were also performed on brain tissues. The results showed that groups that received tramadol (therapeutic and abuse) suffered from weight loss. Tramadol abuse group and combination abuse group showed significant decrease in the activities of I, III, and IV complexes but not in the activity of complex II. In conclusion, tramadol but not clonazepam has been found to partially inhibit the activities of respiratory chain complexes I, III, and IV but not the activity of complex II and such inhibition occurred only at doses that exceeded the maximum recommended adult human daily therapeutic doses. This result explains the clinical and histopathological effects of tramadol, such as seizures and red neurons (marker for apoptosis), respectively.

Role of phosphodiesterase 4-mediated cyclic AMP signaling in pharmacotherapy for substance dependence.

The harmful effects caused by misuse of psychoactive substances have raised both medical and social problems. Substance dependence is a chronic relapsing disorder, which appears to involve neuroadaptive changes in cellular signaling and downstream gene expression. The unchanged consumption of present substances and increasing demand for new psychostimulants make the development of novel management/treatment strategies challenging. Emerging evidence has shown that the cyclic AMP (cAMP) signaling cascade plays a critical role in the initiation and development of dependence. Thus, phosphodiesterase 4 (PDE4), the primary hydrolytic enzyme for intracellular cAMP, is considered a potential target for future therapeutics dealing with prevention and intervention of substance dependence. This implication is supported by recent data from preclinical studies, and the rapid development of PDE4 inhibitors. Taken together, specific inhibitors of PDE4 and its subtypes possibly represent a novel class of pharmacotherapies for the prevention and abstinence of substance dependence. Here we discuss the modulatory role of cAMP signal transduction in the process of substance dependence and highlight recent evidence that PDE4 inhibitors might be a promising approach to substance dependence therapy.

Development of an in vitro cytochrome P450 cocktail inhibition assay for assessing the inhibition risk of drugs of abuse.

Drugs of abuse are not tested for cytochrome P450 (CYP) inhibition potential before distribution. Therefore, a cocktail assay should be developed for testing the inhibition potential for all relevant CYPs. The following CYP test substrates and selective inhibitors were incubated in pooled human liver microsomes: phenacetin (alpha-naphthoflavone for CYP1A2), coumarin (tranylcypromine, CYP2A6), bupropion (sertraline, CYP2B6), amodiaquine (trimethoprim, CYP2C8), diclofenac (sulfaphenazole, CYP2C9), omeprazole (fluconazole, CYP2C19), dextromethorphan (quinidine, CYP2D6), chlorzoxazone (clomethiazole, CYP2E1), testosterone (verapamil, CYP3A). Samples were analyzed after protein precipitation using a Thermo Fisher Q-Exactive LC-high-resolution-MS/MS. The IC50 values were calculated by plotting the concentration of the formed metabolite, relative to the control sample, over the logarithm of the inhibitor concentration. They were determined either for single substrate or the cocktail incubation. Unfortunately, the cocktail assay had to be split because of interferences during incubation caused by substrates or metabolites, but the mixture of both incubates could be analyzed in one analytical run. The IC50 values determined in the single substrate or both cocktail incubations were comparable among themselves and with published data. In conclusion, the new inhibition cocktail assay was reproducible and applicable for testing the inhibition potential of drugs of abuse as exemplified for 2,5-dimethoxy-4-iodo-amfetamine (DOI).

[Effect of electroacupuncture intervention at different time-points in a day on expression of c-fos and neuronal nitric oxide synthase in medial prefrontal cortex in ketamine addiction rats].

UNLABELLED: To observe the effects of electroacupuncture(EA) stimulation of "Zusanli"(ST 36) and "Sanyinjiao"(SP 6) at different time-points of a day on the expression of c-fos and neuronal nitric oxide synthase (nNOS) in the medial prefrontal cortex (mPFC) in rats with ketamine addiction. METHODS: A total of 56 SD rats were randomized into control group, saline group, model group and EA group. The EA group was further divided into Zi-shi (23 : 00), Mao-shi (05 : 00), Wu-shi (11 : 00) and You-shi (17 : 00) subgroups (n = 8 in each group or subgroup). Ketamine addiction model was established by intraperitoneal administration of ketamine (100 mg/kg), once a day for 7 days. EA (2 Hz, 3 V) was applied to unilateral "Zusanli" (ST 36) and "Sanyinjiao" (SP 6) acupoints for 30 min, once daily for 7 days. The expression of c-fos and nNOS in the mPFC was detected by immunohistochemistry. RESULTS: Following EA intervention for 7 days, the animals' daily life activities including body stretching, standing, jumping, circling, falling on the back and fur-licking in the EA group (Wu-shi and You-shi subgroups) were close to those of the normal control and saline groups, being much better than the model group. Compared with the normal control group and saline group, the expression levels of c-fos and nNOS in the mPFC in the model group were significantly upregulated (P < 0.05). Compared with the model group, the expression levels of both c-fos and nNOS were considerably down-regulated in the Wu-shi (11 : 00) and You-shi (17 : 00) subgroups (P < 0.05), rather than in the Zi-shi (23 : 00) and Mao-shi (05 : 00) subgroups (P > 0.05). CONCLUSION: EA of ST 36 and SP 6 at 11 : 00 and 17 : 00 can decrease the expression o fc-fos and nNOS in the mPFC in ketamine addiction rats, which may contribute to its effects in improving the rats' behavior activity.

Therapeutic potential of monoacylglycerol lipase inhibitors.

Marijuana and aspirin have been used for millennia to treat a wide range of maladies including pain and inflammation. Both cannabinoids, like marijuana, that exert anti-inflammatory action through stimulating cannabinoid receptors, and cyclooxygenase (COX) inhibitors, like aspirin, that suppress pro-inflammatory eicosanoid production have shown beneficial outcomes in mouse models of neurodegenerative diseases and cancer. Both cannabinoids and COX inhibitors, however, have untoward effects that discourage their chronic usage, including cognitive deficits and gastrointestinal toxicity, respectively. Recent studies have uncovered that the serine hydrolase monoacylglycerol lipase (MAGL) links the endocannabinoid and eicosanoid systems together through hydrolysis of the endocannabinoid 2-arachidonoylglycerol (2-AG) to provide the major arachidonic acid (AA) precursor pools for pro-inflammatory eicosanoid synthesis in specific tissues. Studies in recent years have shown that MAGL inhibitors elicit anti-nociceptive, anxiolytic, and anti-emetic responses and attenuate precipitated withdrawal symptoms in addiction paradigms through enhancing endocannabinoid signaling. MAGL inhibitors have also been shown to exert anti-inflammatory action in the brain and protect against neurodegeneration through lowering eicosanoid production. In cancer, MAGL inhibitors have been shown to have anti-cancer properties not only through modulating the endocannabinoid-eicosanoid network, but also by controlling fatty acid release for the synthesis of protumorigenic signaling lipids. Thus, MAGL serves as a critical node in simultaneously coordinating multiple lipid signaling pathways in both physiological and disease contexts. This review will discuss the diverse (patho)physiological roles of MAGL and the therapeutic potential of MAGL inhibitors in treating a vast array of complex human diseases.

[Effects of electroacupuncture intervention at different time in A day on expression of tyrosine hydroxylase and C-fos in nucleus accumbens in ketamine addiction rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) intervention at different time in a day on the expression of tyrosine hydroxylase (TH) and c-fos in the Nucleus Accumbens (NAc) so as to explore its mechanism underlying improvement of ketamine addiction. METHODS: A total of 56 Sprague-Dawley rats were randomized into normal control, normal saline (2 mL/kg), model and EA groups. The EA group was subdivided into Zi-Shi (23:00), Mao-Shi (05:00), Wu-Shi (11:00) and You-Shi (17: 00) subgroups. Ketamine addiction model was established by intraperitoneal administration of ketamine (100 mg/kg), once a day for 7 days. EA (2 Hz, 3 V) was applied to unilateral "Zusanli" (ST 36) and "Sanyinjiao" (SP 6) for 30 min, once daily for 7 days. The expression of TH and c-fos in the NAc was detected by immunohistochemistry. RESULTS: Compared with the normal control group and normal saline group, the numbers of TH and c-fos immunoreaction (IR)-positive neurons in NAc in the model group were upregulated significantly (P < 0.01). Compared with the model group, the expression levels of both TH and c-fos IR-positive neurons were down-regulated significantly in the Wu-Shi(11:00) and You-Shi (17:00) subgroups (P < 0.01), rather than in the Zi-Shi and Mao-Shi subgroups (P > 0.05). CONCLUSION: EA of "Zusanli" (ST 36) and "Sanyinjiao" (SP 6) at 11:00 and 17:00 of the daytime can down-regulate ketamine addiction induced increase of expression of TH and c-fos in the NAc in ketamine addiction rats, which may contribute to its effect in relieving ketamine addiction symptoms in clinic.

Protective role for the disulfide isomerase PDIA3 in methamphetamine neurotoxicity.

Methamphetamine abuse continues to be a worldwide problem, damaging the individual user as well as society. Only minimal information exists on molecular changes in the brain that result from methamphetamine administered in patterns typical of human abusers. In order to investigate such changes, we examined the effect of methamphetamine on the transcriptional profile in brains of monkeys. Gene expression profiling of caudate and hippocampus identified protein disulfide isomerase family member A3 (PDIA3) to be significantly up-regulated in the animals treated with methamphetamine as compared to saline treated control monkeys. Methamphetamine treatment of mice also increased striatal PDIA3 expression. Treatment of primary striatal neurons with methamphetamine revealed an up-regulation of PDIA3, showing a direct effect of methamphetamine on neurons to increase PDIA3. In vitro studies using a neuroblastoma cell line demonstrated that PDIA3 expression protects against methamphetamine-induced cell toxicity and methamphetamine-induced intracellular reactive oxygen species production, revealing a neuroprotective role for PDIA3. The current study implicates PDIA3 to be an important cellular neuroprotective mechanism against a toxic drug, and as a potential target for therapeutic investigations.

Elevated aspartate and alanine aminotransferase levels and natural death among patients with methamphetamine dependence.

BACKGROUND: Methamphetamine is one of the fastest growing illicit drugs worldwide, causing multiple organ damage and excessive natural deaths. The authors aimed to identify potential laboratory indices and clinical characteristics associated with natural death through a two-phase study. METHODS: Methamphetamine-dependent patients (n = 1,254) admitted to a psychiatric center in Taiwan between 1990 and 2007 were linked with a national mortality database for causes of death. Forty-eight subjects died of natural causes, and were defined as the case subjects. A time-efficient sex- and age-matched nested case-control study derived from the cohort was conducted first to explore the potential factors associated with natural death through a time-consuming standardized review of medical records. Then the identified potential factors were evaluated in the whole cohort to validate the findings. RESULTS: In phase I, several potential factors associated with natural death were identified, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), comorbid alcohol use disorder, and the prescription of antipsychotic drugs. In phase II, these factors were confirmed in the whole cohort using survival analysis. For the characteristics at the latest hospital admission, Cox proportional hazards models showed that the adjusted hazard ratios for natural death were 6.75 (p<0.001) in the group with markedly elevated AST (>80 U/L) and 2.66 (p<0.05) in the group with mildly elevated AST (40-80 U/L), with reference to the control group (<40 U/L). As for ALT, the adjusted hazard ratios were 5.41 (p<0.001), and 1.44 (p>0.05). Comorbid alcohol use disorder was associated with an increased risk of natural death, whereas administration of antipsychotic drugs was not associated with lowered risk. CONCLUSIONS: This study highlights the necessity of intensive follow-up for those with elevated AST and ALT levels and comorbid alcohol use disorder for preventing excessive natural deaths.

A COMT gene haplotype associated with methamphetamine abuse.

INTRODUCTION: Methamphetamine (MAMP) use is highly associated with psychiatric disorders with 12-13% of MAMP-dependent patients experiencing psychotic symptoms. Substance abuse and dependence may primarily involve the mesolimbic pathway and dopaminergic brain structures. It follows that dopaminergic genes, particularly COMT (encoding catechol-O-methyltransferase) and its val158met polymorphism (rs4680), are natural candidates for susceptibility loci to addiction. We have previously found an association with rs4680 and MAMP addiction. METHODS: We present additional genotyping of rs165599 in 423 cases and 502 controls of a Taiwanese MAMP user sample. We carried out an in-silico evaluation of rs165599 for a possible impact on microRNA binding or UTR stability. We also carried out a review of transcript sequences across the COMT 3'UTR. RESULTS: Genotype counts were (cases/controls): AA 94/110, AG 198/210 and GG 93/109. There were no significant allele or genotype differences between cases and controls for rs165599. However, a haplotype main effect was detected using both rs4680 and rs165599 using the χ²-test in UNPHASED. The global P-value was P=0.0044 with the effect appearing to derive from one haplotype that is underrepresented in cases: A/G for rs4680/rs165599 (haplotype P=0.001). rs165599 is a single nucleotide polymorphism located in the COMT 3' untranslated region (UTR), a noncoding transcript region subject to posttranscriptional down-regulation by mechanisms such as microRNA binding. A review of transcript sequences across the COMT 3'UTR found evidence to suggest antisense interference of COMT from the 3'UTR of the neighbouring 'Armadillo repeat gene deleted in velocardiofacial syndrome' gene.

Constant activity of glutamine synthetase after morphine administration versus proteomic results.

Glutamine synthetase is a key enzyme which has a regulatory role in the brain glutamate pool. According to previously published proteomic analysis, it was shown that the expression level of this enzyme is affected by morphine administration. In our study, we examined the activity of glutamine synthetase in various structures of rat brain (cortex, striatum, hippocampus and spinal cord) that are biochemically and functionally involved in drug addiction and antinociception caused by morphine. We were not able to observe any significant changes in the enzyme activity between morphine-treated and control samples despite previously reported changes in the expression levels of this enzyme. These findings stressed the fact that changes observed in the expression of particular proteins during proteomic studies may not be correlated with its activity.