Association of Serotonin Transporter Gene (5-HTTLPR/rs25531) Polymorphism with Comorbidities of Panic Disorder.

INTRODUCTION: Panic disorder (PD) has many comorbidities such as depression, bipolar disorder (BPD), and agoraphobia (AG). PD is a moderately heritable anxiety disorder whose pathogenesis is not well understood. Recently, a tri-allelic serotonin transporter (5-HTTLPR/rs25531) polymorphism was reported to be more sensitive to personality traits compared to the bi-allelic 5-HTTLPR polymorphism. We hypothesized that the 5-HTTLPR/rs25531 polymorphism may lead to a pathological anxious state depending on the presence or absence of a comorbidity in PD. METHODS: In this study, we investigated the relationship between comorbidities in PD and tri-allelic 5-HTTLPR polymorphisms. A total of 515 patients with PD (148 males, 367 females) were genotyped, and the Revised NEO Personality Inventory as well as anxiety-related psychological tests were administered. Depression, BPD, and AG were diagnosed as comorbidities. RESULTS: For the tri-allele 5-HTTLPR genotype, a significant interaction effect was found between openness to experience and comorbid depression. Examination of the interaction between AG and the tri-allelic 5-HTTLPR genotype revealed that L' allele carriers are associated with higher trait anxiety than the S'S' genotype group in PD without AG. CONCLUSION: Some anxiety and personality traits can be characterized by the tri-allelic gene effect of 5-HTTLPR. These results suggest that tri-allelic 5-HTTLPR genotypes have genetic effects on the presence of comorbidities of PD.

Size-classified aerosol-bound heavy metals and their effects on human health risks in industrial and remote areas in Japan.

Airborne aerosols were collected in six size classes (PM<0.1, PM0.1-0.5, PM0.5-1, PM1-2.5, PM2.5-10 and PM>10) to investigate aerosol health risks in remote and industrial areas in Japan. We focused on heavy metals and their water-dispersed fractions. The average concentration of heavy metals was 18 ± 25-86 ± 48 ngm-3 for PM<0.1, 46 ± 19-154 ± 80 for PM0.5-1 ngm-3, 98 ± 49-422 ± 186 ngm-3 for PM1-2.5, 321 ± 305-1288 ± 727 ngm-3 for PM2.5-10 and 65 ± 52-914 ± 339 ngm-3 or PM>10, and these concentrations were higher in industrial areas. Heavy metals emitted from domestic anthropogenic sources were added to the long-range transport component of the aerosols. The water-dispersed fraction of heavy metals contained 3.3-40.1% of the total heavy metals in each size class. The relative contribution of Zn and other species (As, Cd, Cr, Ni, Pb, Mn, V and Cu) increased in the water-dispersed fraction. Smaller particles contained greater proportions of the water-dispersed heavy metal fraction. Carcinogenic risk (CR) and the hazard index (HI) were estimated for each size class. The CR of carcinogens was at acceptable levels (<1 ×10-6) for five particle size fractions. The HI values for carcinogens and noncarcinogens were also below acceptable levels (<1) for the same five size fractions. The estimated CR and HI values were dominated by contributions from the inhalation process.

Shared transethnic genetic basis of panic disorder and psychiatric and related intermediate phenotypes.

Panic disorder (PD), a common anxiety disorder, is modestly heritable. The genetic basis of anxiety disorders overlaps with that of other psychiatric disorders and their intermediate phenotypes in individuals of European ancestry. Here, we investigated the transethnic polygenetic features shared between Japanese PD patients and European patients with psychiatric disorders and their intermediate phenotypes by conducting polygenic risk score (PRS) analyses. Large-scale European genome-wide association study (GWAS) datasets (n = 7,556-1,131,881) for ten psychiatric disorders and seven intermediate phenotypes were utilized as discovery samples. PRSs derived from these GWASs were calculated for Japanese target subjects [718 PD patients and 1,717 healthy controls (HCs)]. The effects of these PRSs from European GWASs on the risk of PD in Japanese patients were investigated. The PRSs from European studies of anxiety disorders were marginally higher in Japanese PD patients than in HCs (p = 0.013). Regarding other psychiatric disorders, the PRSs for depression in European patients were significantly higher in Japanese PD patients than in HCs (p = 2.31×10-4), while the PRSs for attention-deficit/hyperactivity disorder in European patients were nominally lower in Japanese PD patients than in HCs (p = 0.024). Regarding health-related, personality-based and cognitive intermediate phenotypes, the PRSs for loneliness (especially isolation) in European individuals were significantly higher in Japanese PD patients than in HCs (p = 9.02×10-4). Furthermore, Japanese PD patients scored nominally higher than HCs in PRSs for neuroticism in European people (p = 3.37×10-3), while Japanese PD patients scored nominally lower than HCs in PRSs for tiredness (p = 0.025), educational attainment (p = 0.035) and cognitive function (p = 9.63×10-3). Our findings suggest that PD shares transethnic genetic etiologies with other psychiatric disorders and related intermediate phenotypes.

Effects of hemagglutinin-neuraminidase protein mutations on cell-cell fusion mediated by human parainfluenza type 2 virus.

The monoclonal antibody M1-1A, specific for the hemagglutinin-neuraminidase (HN) protein of human parainfluenza type 2 virus (HPIV2), blocks virus-induced cell-cell fusion without affecting the hemagglutinating and neuraminidase activities. F13 is a neutralization escape variant selected with M1-1A and contains amino acid mutations N83Y and M186I in the HN protein, with no mutation in the fusion protein. Intriguingly, F13 exhibits reduced ability to induce cell-cell fusion despite its multistep replication. To investigate the potential role of HPIV2 HN protein in the regulation of cell-cell fusion, we introduced these mutations individually or in combination to the HN protein in the context of recombinant HPIV2. Following infection at a low multiplicity, Vero cells infected with the mutant virus H-83/186, which carried both the N83Y and M186I mutations, remained as nonfused single cells at least for 24 h, whereas most of the cells infected with wild-type virus mediated prominent cell-cell fusion within 24 h. On the other hand, the cells infected with the mutant virus, carrying either the H-83 or H-186 mutation, mediated cell-cell fusion but less efficiently than those infected with wild-type virus. Irrespective of the ability to cause cell-cell fusion, however, every virus could infect all the cells in the culture within 48 h after the initial infection. These results indicated that both the N83Y and M186I mutations in the HN protein are involved in the regulation of cell-cell fusion. Notably, the limited cell-cell fusion by H-83/186 virus was greatly promoted by lysophosphatidic acid, a stimulator of the Ras and Rho family GTPases.

Dopamine D2 and serotonin 5-HT1A receptors mediate the actions of aripiprazole in mesocortical and mesoaccumbens transmission.

The antipsychotic agent aripiprazole acts as a partial agonist of dopamine D2 and serotonin 5-HT1A receptors. However, the detailed actions of aripiprazole in mesolimbic and mesocortical transmission remain to be clarified. To address this, we examined the effects of systemic and local administrations of aripiprazole on extracellular levels of dopamine and GABA in medial prefrontal cortex (mPFC), nucleus accumbens (NAc), and anterior (aVTA) and posterior (pVTA) ventral tegmental areas. Intraperitoneal injection of aripiprazole (0.5mg/kg) increased dopamine release in mPFC without affecting those in aVTA, pVTA, or NAc, whereas 10mg/kg decreased the release in all four regions. Local sulpiride administration in aVTA increased concentration-dependently dopamine release in both aVTA and NAc without affecting that in mPFC, whereas local aripiprazole administration in aVTA concentration-dependently decreased dopamine release in aVTA and mPFC without affecting that in NAc. Blockade of 5-HT1A receptor in aVTA produced aripiprazole-induced dopamine release in aVTA and prevented the aripiprazole-induced reduction of dopamine release in mPFC. Local administration of aripiprazole in mPFC increased dopamine and decreased GABA releases, whereas local administration of sulpiride had no effect on dopamine or GABA. In mPFC, blockade of 5-HT1A receptor prevented the aripiprazole-induced dopamine elevation and GABA reduction; however, under the activation of GABA(A) receptor, local perfusion with aripiprazole in mPFC decreased GABA release without affecting dopamine release. The results suggested that the combination of 5-HT1A and D2 partial agonistic actions of aripiprazole against mesocortical and mesoaccumbens transmission, explains, at least in part, the atypical antipsychotic properties of aripiprazole. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.

Novel δ1-receptor agonist KNT-127 increases the release of dopamine and L-glutamate in the striatum, nucleus accumbens and median pre-frontal cortex.

The effects of systemic δ1-agonist on neurotransmission remains obscure, since no selective δ1-agonist exists that can penetrate the blood-brain barrier. Recently, we succeeded in synthesizing a putative δ1-receptor agonist, KNT-127, which has been demonstrated the effectiveness of systemic administration against anxiety and depressive-like behavior. To clarify the functional selectivity of KNT-127 and neurotransmission regulating system of δ1-receptor, the present study investigated the interaction between KNT-127 and δ-receptor antagonists on the release of dopamine, L-glutamate and GABA in nucleus accumbens (NAc), striatum and median pre-frontal cortex (mPFC) using multi-probe microdialysis. Intraperitoneal administration of KNT-127 increased the release of dopamine and L-glutamate in three regions, but decreased and increased GABA releases in respective NAc and mPFC without affecting that in striatum. The effects of KNT-127 in the three regions were abrogated by δ1-antagonist but not by δ2-antagonist. MK801 inhibited KNT-127-induced dopamine release in striatum and NAc, but enhanced that in mPFC, inhibited KNT-127-induced mPFC GABA release without affecting KNT-127-induced GABA reduction in NAc. Muscimol enhanced KNT-127-induced dopamine release in mPFC. Sulpiride inhibited KNT-127-induced reduction of GABA release in NAc. The results indicated that KNT-127 is a selective δ1-agonist, and suggested that δ1-receptor directly activates the release of dopamine and L-glutamate in the striatum, NAc and mPFC, but not that of GABA in the three regions. δ1-receptor indirectly inhibited GABA release in NAc via activated dopaminergic transmission, while δ1-receptor indirectly enhanced GABA release in mPFC via activated glutamatergic transmission.

Levetiracetam inhibits neurotransmitter release associated with CICR.

To define the antiepileptic mechanisms of levetiracetam (LEV), the present study determined the concentration-dependent effects of locally perfused LEV on the releases of norepinephrine, dopamine, serotonin, l-glutamate and GABA induced by 50 mMK(+)-evoked stimulation and agonists of ryanodine receptor (RyR) and inositol-triphosphate receptor (IP3R) in the median prefrontal cortex (mPFC) using in vivo microdialysis. Local perfusion with LEV (10, 30 and 100 µM) alone did not affect the extracellular levels of all neurotransmitters in the mPFC. The release of neurotransmitters induced by K(+)-evoked stimulation was inhibited by perfusion with LEV in a concentration-dependent manner, and those induced by agonists of RyR and IP3R were also inhibited by LEV. Specifically, the RyR-induced release was inhibited by 10 µM LEV, whereas the IP3R-induced release was inhibited by 100 µM LEV, but not by 10 or 30 µM LEV. The above results suggest that LEV has little effect on the components of normal synaptic transmission but selectively inhibits transmission induced by neuronal hyperactivation. Thus, the mechanisms of the antiepileptic and neuroprotective actions of LEV seem to be mediated, at least in part, through the combination of these two inhibitory effects on depolarization-induced and CICR-associated neurotransmitter releases.