Possible association of nicotinic acetylcholine receptor gene (CHRNA4 and CHRNB2) polymorphisms with nicotine dependence in Japanese males: an exploratory study.

INTRODUCTION: Smoking is a leading global cause of avoidable mortality. It has been reported that the nicotinic acetylcholine receptor (CHRNA4 and CHRNB2) genes might be associated with smoking behavior in several ethnic populations. However, no study between the 2 genes and nicotine dependence (ND) using a Japanese population has been reported. METHODS: We examined the association between ND and 5 single nucleotide polymorphisms (SNPs) within the CHRNA4 and 3 SNPs within the CHRNB2 using a well characterized sample of 558 Japanese healthy male workers with a relatively homogeneous background. The Fagerström test for nicotine dependence (FTND) was used to quantify the degree of ND. Additionally, we explored the effect of gene-gene interactions of the 2 genes on ND. RESULTS: We found CHRNB2 rs4845652 genotypes to be associated with FTND scores under an additive genetic model: rs4845652 T-allele carriers had lower ND levels (p=0.038; when adjusted for smoking duration: p=0.052). Furthermore, we demonstrated a possible gene-gene interaction of CHRNA4 and CHRNB2 on ND in a dose-dependent manner: those smokers with CHRNA4 rs1044397 GG or GA genotypes along with CHRNB2 rs4845652 CC genotype are likely to demonstrate higher ND scores. DISCUSSION: These findings suggest that CHRNB2 rs4845652 T-allele carriers may be associated with lower levels of ND, and that certain allelic combinations of CHRNA4 and CHRNB2 might be correlated with higher ND levels. This preliminary study has certain limitations (issues such as sample size/power and multiple testing) that need to be taken into account, and the present work thus has an experimental nature.

Allelic association of the neuronal nitric oxide synthase (NOS1) gene with schizophrenia.

Nitric oxide (NO) has been identified as a widespread and multifunctional biological messenger molecule in the central nervous system (CNS), with possible roles in neurotransmission, neurosecretion, synaptic plasticity, and tissue injury in many neurological disorders, including schizophrenia. Neuronal NO is widely produced in the brain from L-arginine catalyzed by neuronal NO synthase (NOS1). We therefore hypothesized that the NOS1 gene may play a role in the pathophysiology of schizophrenia. In the present study, we examined the genetic association between a novel single nucleotide polymorphism (SNP: a C-->T transition located 276 base pairs downstream from the translation termination site) of the human NOS1 gene, which is located in chromosome 12q24, and schizophrenia (215 Japanese patients with schizophrenia and 182 healthy controls). The allele frequencies of the polymorphism in exon 29 of the NOS1 gene differed significantly between patients with schizophrenia and controls (chi(2) = 20.10, df = 1, P = 0.000007; relative risk = 1.92; 95% confidence interval = 1.44-2.55). Our results suggest that the NOS1 gene polymorphism may confer increased susceptibility to schizophrenia.

Studies toward the total synthesis of popolohuanone E: enantioselective synthesis of 8-O-methylpopolohuanone E.

[structure: see text]. 8-O-methylpopolohuanone E (2) was synthesized in a highly convergent manner starting from the cis-fused decalin derivative accessible from the (-)-Wieland-Miescher ketone analogue. The synthetic method features a biogenetic-type annulation of the phenolic and quinone segments to regioselectively construct the central tricyclic ring system as the key step.

Novel polymorphism in the 5'-upstream region of the human 5-HT6 receptor gene and schizophrenia.

The localization of 5-hydroxytryptamine6 (5-HT6) receptor in the limbic and cortical regions, and the high affinity of atypical antipsychotic drugs such as clozapine for the receptor, suggest the possible involvement of the receptor in the pathogenesis of schizophrenia. In this study, we searched systematically for polymorphisms in the 5'-upstream region of the human 5-HT6 receptor gene. We identified a trinucleotide repeat polymorphism, (GCC)2/3, at a nucleotide position between -1093 and -1085 bp upstream from the translation start site. Subsequent case-control association study did not demonstrate significant differences of genotype and allele frequency between 206 controls and 246 patients with schizophrenia. Our results suggest that the 5-HT6 receptor gene polymorphism does not confer increased susceptibility to schizophrenia.

Association analysis between two functional dopamine D2 receptor gene polymorphisms and schizophrenia.

The dopamine D2 receptor (DRD2) gene has been listed as one of the candidate genes for susceptibility to schizophrenia. To date, a significant association between schizophrenia and two functional DRD2 gene polymorphisms, Ser311Cys and -141C Ins/Del, in Japanese samples, has been reported by Arinami et al. [1994: Lancet 343:703-704; 1997: Hum Mol Genet 6:577-582]. In the present study, we replicated the findings of Arinami et al. [1994: Lancet 343:703-704; 1997: Hum Mol Genet 6:577-582] in the same ethnic groups (Japanese samples) with the same polymorphisms (Ser311Cys and -141C Ins/Del). We genotyped these two polymorphisms for 241 patients and for 201 controls. Neither polymorphism was associated with schizophrenia. Moreover, in a haplotype analysis of the present sample, combined pairs of two polymorphisms provided no evidence for the association of either haplotype with schizophrenia. Our findings indicate that an association between the two functional DRD2 gene polymorphisms, Ser311Cys and -141C Ins/Del, and schizophrenia is unlikely.

E1 mice epilepsy shows genetic polymorphism for S-Adenosyl-L-homocysteine hydrolase.

E1 mice are an animal model of human epilepsy (idiopathic complex partial seizures). We have previously demonstrated abrupt poly(A)(+) RNA expression in liver from 1-day-old E1 mouse [Mita et al., 1991. Devl. Brain Res. 64, 27-35]. In the present study, we constructed a cDNA library of the poly(A)(+) RNA. By analyzing cDNA clones and nucleotide sequences, we found a clone that was homologous to a rat gene of S-adenosyl-L-homocysteine hydrolase (EC 3.3.1.1.) (SAHH) (a key enzyme in the active methyl transfer pathway) and showed the gene polymorphism/RFLP(PstI) between the epileptic strain, E1, and the non-epileptic mother strain, ddY, as indicated in a gel electrophoresis by cleaving 2.6 kb with PstI into 1.9 kb and 0.7 kb fragment bands. F1(E1xddY) showed the heterozygosity. An attempt to determine the mutation on the genomic SAHH gene in the E1 disclosed a single nucleotide polymorphism indicated by a C-->T transition in the 8th intron, by which the PstI site was created. SAHH enzymatic activity in the liver in 1-day-old E1 mice was slight (approximately 10%), and in fact was significantly lower than that of the control ddY. Results suggested that the abrupt primary mRNA transcribed on the SAHH gene in the liver of 1-day-old E1 mice was processed partially or incompletely because of the presence of the point mutation in the intron. Accordingly, poor energy supply by the insufficient SAHH enzymatic activity in the brain postnatally may be responsible for epileptogenesis in this animal model. It is concluded that a single nucleotide SAHH gene polymorphism may be associated with epilepsy in E1 mice.

Clara cell secretory protein (CC16) gene polymorphism and schizophrenia in humans.

An increasing amount of evidence suggests that the pathophysiology of schizophrenia is associated with activation of the inflammatory response system, as indicated by lower serum concentrations of Clara cell secretory protein (CC16), an endogenous anti-inflammatory protein in patients with schizophrenia. In the present study, we investigated the genetic association between a functional polymorphism (A38G) in human CC16 gene and schizophrenia (248 Japanese schizophrenic patients and 206 healthy controls). No significant positive association between the CC16 gene polymorphism and schizophrenia was observed. In addition, even when schizophrenic patients were divided into those with a positive family history for schizophrenia and with a negative family history for schizophrenia, no significant association with A38G polymorphism of the CC16 gene was observed. Our results suggest that the CC16 gene polymorphism do not confer increased susceptibility for schizophrenia.

Association between three functional polymorphisms of dopamine D2 receptor gene and tardive dyskinesia in schizophrenia.

The dopamine D2 receptor (DRD2) gene is considered one of the candidate genes contributing to the development of tardive dyskinesia (TD). In the present study, we investigated the genetic association between three functional polymorphisms (Ser311Cys, -141C Ins/Del and TaqI A) in the DRD2 gene and TD (200 patients with schizophrenia: 44 with TD and 156 without TD). No significant difference in the allelic and genotypic distribution between patients with TD and those without TD was observed. However, we found a slightly significant association between the -141C Ins/Del polymorphism and the total Abnormal Involuntary Movement Scale (AIMS) score (P = 0.037). The significant association between the -141C Ins/Del polymorphism and the total AIMS score did not remain after the regression analysis was taken into account (P = 0.14). Our results suggest that that three functional polymorphisms in DRD2 may not play a major role in the occurrence of TD.

Palladium(0)-catalyzed cross-benzannulation between conjugated enynes. reactivity-controlled synthesis of multifunctionalized benzenes

The synthesis of multifunctionalizbenzenes such as polysubstituted alkoxycarbonyl- or cyanostyrenes was carried out by the regioselective cross-benzannulation between conjugated enynes in the presence of Pd(PPh(3))(4).

Relationship between serum cholesterol levels and meta-chlorophenylpiperazine-induced cortisol responses in healthy men and women.

We investigated the effect of cholesterol on serotonergic receptor function in 20 healthy male and 10 healthy female subjects using cortisol responses to meta-chlorophenylpiperazine (m-CPP) neuroendocrine challenge tests. M-CPP, a metabolite of the antidepressant trazodone, has been widely used in psychopharmacology research as a probe of serotonin function. In the human brain, m-CPP binds both to various serotonergic receptors, mainly 5-HT(2C), and to alpha(2)-adrenoceptors. After an overnight fast, the subjects received m-CPP (0.5 mg/kg) or identical placebo capsules orally in a randomized, double blind, crossover design. Blood was obtained for measurement of cholesterol and cortisol. In some analyses, especially in males, there were significant positive correlations between serum cholesterol levels and cortisol responses. These findings suggest the possibility that serum cholesterol levels may be positively associated with serotonergic receptor function. The existence of such an association may provide an explanation for reported increases in depression, suicide and violence in individuals with low or lowered cholesterol.

Manganese superoxide dismutase gene polymorphism and schizophrenia: relation to tardive dyskinesia.

There has been increasing evidence that deranged superoxide dismutase (SOD) activities might be a risk factor for schizophrenia and/or tardive dyskinesia (TD). In the present study, we investigated the genetic association between a functional polymorphism (Ala-9Val) in the human manganese (Mn) SOD gene and schizophrenia or TD (192 schizophrenics: 39 with TD and 153 without TD; 141 controls). No significant differences in the allelic or genotypic distribution between schizophrenics and controls were observed. However, we did find a significant difference in genotypic distribution between schizophrenics with and those without TD (p =. 03). Moreover, decreased -9Ala (mutant) allele was found among patients with TD (p =.02; odds ratio = 0.29; 95% confidence interval = 0.10-0.83). In conjunction with previous findings of increased free radicals and decreased SOD activities in TD subjects, these results suggest that the -9Ala (high activity) MnSOD allele may play a role in protecting against susceptibility to TD in schizophrenics.

Prediction of lithium response using. m-chlorophenylpiperazine challenge test: A preliminary finding.

It is important to be able to predict a response to lithium before lithium administration because it usually takes 2 or 3 weeks for lithium to manifest its effect sufficiently. We hypothesized that lithium responders have a high post-synaptic serotonergic receptor function, whereas non-responders have low one. This is because it has been suggested that lithium's primary actions on the serotonergic neuron may be presynaptic and several reports have shown that lithium enhances serotonin synthesis and secretion at the presynaptic serotonergic neuron. As a preliminary study, we investigated the relationship between several responses to meta-chlorophenylpiperazine (a serotonergic agonist) reflecting the serotonergic receptor function and the clinical lithium response of 10 patients. No significant relationship between hormone responses and improvement ratios was found. However, there were significant relationships found between 'anger' during the challenge test and the improvement ratio and between 'tension' during the test and the improvement ratio. Thus, it seems that the hormone response to a serotonergic agonist is not useful for predicting lithium response. However, subjective responses such as anger and tension to a serotonergic agonist are possible candidates for predicting lithium response. In any case, further studies with larger numbers of participants are required to investigate whether subjective responses to a serotonergic agonist are useful for predicting lithium response.

Synapsin III gene polymorphisms and schizophrenia.

Synapsins are synaptic vesicle-associated phosphoproteins and are thought to play crucial roles in synaptogenesis and neurotransmitter release. Synaptic abnormalities have been reported in the pathophysiology of schizophrenia. In addition, the synapsin III gene, a member of the synapsin gene family, has been located at 22q12-13, which has been suggested as a potential susceptibility locus for schizophrenia. We investigated a genetic association between schizophrenia and the synapsin III gene polymorphisms (-631C/G and -196G/A) in 160 schizophrenic patients and 153 controls. No significant positive association between either polymorphism and schizophrenia was observed. Furthermore, no significant association was observed between either polymorphism and the diagnostic subtypes. Our results suggested that the synapsin III gene polymorphisms do not confer increased susceptibility to schizophrenia.

Polymorphisms of the sigma(1) receptor gene in schizophrenia: An association study.

Possible involvement of sigma receptors in the pathogenesis of schizophrenia has been suggested. In this study we searched systematically for polymorphisms in the 5'-franking region of the sigma(1) receptor. Genetic variation in this region could reduce the expression of the gene, and this suggestion is compatible with findings of reduced sigma binding sites in several cortical regions of schizophrenia. We confirmed G-241T and G-240T polymorphisms; these two consecutive polymorphisms were resolved to be in complete linkage disequilibrium with each other by single-strand conformation polymorphism (SSCP) analysis. We also identified the A61C (Gln2Pro) polymorphism, which was in almost complete linkage disequilibrium with G-241T/G-240T. There was no significant difference in the distribution of alleles or overall genotypes of the polymorphisms between schizophrenic patients (n = 129) and controls (n = 140). We found slight increased homozygosity for T-241/T-240 and C61 in patients compared with controls using multiple comparison (p = 0. 045). However, the significance did not remain when a Bonferroni correction was made (p = 0.135). These results do not support that the sigma(1) receptor gene plays a major role in the pathogenesis of schizophrenia. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:118-122, 2000.

Polymorphisms of tryptophan hydroxylase gene and the symptomatology of schizophrenia: an association study.

Serotonergic neurotransmission may be involved in the etiology of schizophrenia. We systematically searched for human tryptophan hydroxylase (TPH) coding polymorphisms, and detected a novel pentanucleotide repeat deletion polymorphism (GTTTT)4/5 in TPH intron 1b. We also confirmed A779C intron 7. Neither polymorphism showed a significant association with schizophrenia (182 patients with schizophrenia, 148 controls). A significant association, however, between A779C genotypes and the total Manchester Scale (MS) scores was found in male patients (P = 0.045). Subsequently, a significant association was also found between A779C genotypes and the MS negative symptoms scores in male patients (P = 0.030). These results suggest that the TPH gene may play a role in the negative symptoms in male patients with schizophrenia.

Genetic association analysis between CYP2D6*2 allele and tardive dyskinesia in schizophrenic patients

Previous studies have shown a possible association between tardive dyskinesia (TD) and debrisoquine 4-hydroxylase (CYP2D6) polymorphisms, which result in absent enzyme activity. We have recently found a positive association between TD and the CYP2D6*10 allele, which codes for the intermediate metabolizer (IM) phenotype and is characterized by decreased but not absent CYP2D6 activity in Japanese schizophrenic patients. In addition, the CYP2D6* 2 allele with the HhaI site mutation in exon 6 has also been reported to be an IM allele and a risk factor for Parkinson's disease (PD) in the Japanese population. In the present study, we investigated potential contributions of the CYP2D6*2 allele to TD using case-control and regression analysis in 99 schizophrenic patients. No significant differences in genotypic and allelic frequencies were found between patients with and without TD. Even after using regression analysis to adjust for the confounding variables, there was no significant association of the CYP2D6*2 genotype with either outcome variable, the occurrence of TD or the total AIMS score. These results suggest that the CYP2D6*2 allele may not contribute to the pathogenesis of TD.

A simpler and more accurate equation to predict daily lithium dose.

Recently, the authors suggested that the lithium dose prediction equation created by Zetin and associates cannot always accurately predict a required lithium dose and that the inclusion of renal function data may improve the accuracy of the equation. The charts of 70 patients were reviewed to obtain data regarding factors thought to affect serum lithium concentrations, including renal function, and an equation to estimate the dose intended to achieve an expected concentration was derived by stepwise multiple linear regression. The equation was also applied to 30 other patients to evaluate its accuracy. The authors obtained the following equation: daily lithium carbonate dose (in milligrams) = 100.5 + 752.7 x (expected lithium concentration in millimoles per liter) - 3.6 x (age in years) + 7.2 x (weight in kilograms) - 13.7 x (blood urea nitrogen [BUN] in milligrams per deciliter). When the equation was applied to 30 patients, the mean +/- SD of deviations from the expected concentration was 0.15 +/- 0.30 mmol/L, and 19 patients (63%) had deviations of less than 0.20 mmol/L. On the other hand, when the equation set forth by Zetin and associates was applied to the same patients, the mean +/- SD of deviations from the expected concentration was 0.52 +/- 0.42 mmol/L, and only 6 patients (20%) had deviations of less than 0.20 mmol/L. Although it is necessary to measure BUN levels before starting lithium, this equation may be simpler and more accurate than that offered by Zetin and associates.