Phencyclidine (PCP), a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, increases locomotor activity in rodents and causes schizophrenia-like symptoms in humans. Although activation of the dopamine (DA) pathway is hypothesized to mediate these effects of PCP, the precise mechanisms by which PCP induces its effects remain to be elucidated. The present study investigated the effect of PCP on extracellular levels of DA (DA(ex)) in the striatum and prefrontal cortex (PFC) using in vivo microdialysis in mice lacking the NMDA receptor channel ε1 or ε4 subunit (GluRε1 [GluN2A] or GluRε4 [GluN2D]) and locomotor activity. PCP significantly increased DA(ex) in wildtype and GluRε1 knockout mice, but not in GluRε4 knockout mice, in the striatum and PFC. Acute and repeated administration of PCP did not increase locomotor activity in GluRε4 knockout mice. The present results suggest that PCP enhances dopaminergic transmission and increases locomotor activity by acting at GluRε4.

Opioids are commonly used as effective analgesics for the treatment of acute and chronic pain. However, considerable individual differences have been widely observed in sensitivity to opioid analgesics. We focused on a G-protein-activated inwardly rectifying potassium (GIRK) channel subunit, GIRK2, that is an important molecule in opioid transmission. In our initial polymorphism search, a total of nine single-nucleotide polymorphisms (SNPs) were identified in the whole exon, 5'-flanking, and exon-intron boundary regions of the KCNJ6 gene encoding GIRK2. Among them, G-1250A and A1032G were selected as representative SNPs for further association studies. In an association study of 129 subjects who underwent major open abdominal surgery, the A/A genotype in the A1032G SNP and -1250G/1032A haplotype were significantly associated with increased postoperative analgesic requirements compared with other genotypes and haplotypes. The total dose (mean+/-SEM) of rescue analgesics converted to equivalent oral morphine doses was 20.45+/-9.27 mg, 10.84+/-2.24 mg, and 13.07+/-2.39 mg for the A/A, A/G, and G/G genotypes in the A1032G SNP, respectively. Additionally, KCNJ6 gene expression levels in the 1032A/A subjects were significantly decreased compared with the 1032A/G and 1032G/G subjects in a real-time quantitative PCR analysis using human brain tissues, suggesting that the 1032A/A subjects required more analgesics because of lower KCNJ6 gene expression levels and consequently insufficient analgesic effects. The results indicate that the A1032G SNP and G-1250A/A1032G haplotype could serve as markers that predict increased analgesic requirements. Our findings will provide valuable information for achieving satisfactory pain control and open new avenues for personalized pain treatment.

To clarify the potential role of variability within and around the AKT1 gene in smoking behaviors, we performed a single-nucleotide polymorphism (SNP) analysis of the AKT1 gene in an elderly Japanese cohort. Genotypes of the rs2498794 SNP, which is located in the fifth intron region of the AKT1 gene, were marginally but significantly associated with smoking duration in the total 999 samples of former and current smokers. Interestingly, this SNP had a marginally significant association with individual cancer history (past and current), especially in groups with a shorter smoking duration (<44 years) and fewer cigarettes per day (≤20). These data suggest that the rs2498794 polymorphism of the AKT1 gene is associated with a long smoking duration and may be involved in the predisposition to cancer when the smoking duration is short or the cigarettes per day is rate low.

Data-independent acquisition (DIA) in liquid chromatography (LC) coupled to tandem mass spectrometry (MS/MS) provides comprehensive untargeted acquisition of molecular data. We provide an open-source software pipeline, which we call MS-DIAL, for DIA-based identification and quantification of small molecules by mass spectral deconvolution. For a reversed-phase LC-MS/MS analysis of nine algal strains, MS-DIAL using an enriched LipidBlast library identified 1,023 lipid compounds, highlighting the chemotaxonomic relationships between the algal strains.

The single nucleotide polymorphism (SNP) rs13438494 in intron 24 of PCLO was significantly associated with bipolar disorder in a meta-analysis of genome-wide association studies. In this study, we performed functional minigene analysis and bioinformatics prediction of splicing regulatory sequences to characterize the deep intronic SNP rs13438494. We constructed minigenes with A and C alleles containing exon 24, intron 24, and exon 25 of PCLO to assess the genetic effect of rs13438494 on splicing. We found that the C allele of rs13438494 reduces the splicing efficiency of the PCLO minigene. In addition, prediction analysis of enhancer/silencer motifs using the Human Splice Finder web tool indicated that rs13438494 induces the abrogation or creation of such binding sites. Our results indicate that rs13438494 alters splicing efficiency by creating or disrupting a splicing motif, which functions by binding of splicing regulatory proteins, and may ultimately result in bipolar disorder in affected people.

CXBH mice, known as an "opioid receptor-rich" strain, are a recombinant inbred mouse strain established by crossing the C57BL/6By and BALB/cBy strains. In the present study, we investigated nociceptive and antinociceptive sensitivity in CXBH mice and elucidated the underlying molecular mechanisms. CXBH mice exhibited slightly higher morphine-induced antinociception compared with C57BL/6J and BALB/cBy mice in the hot-plate test but not tail-flick test. CXBH mice exhibited a marked reduction of nociceptive sensitivity, regardless of the type of nociceptive stimulus, with the exception of tail stimulation. Changes in gene expression that corresponded to reduced nociceptive sensitivity in the brains of CXBH mice were observed in 62 transcripts, including pain- and analgesia-related transcripts, in a whole-genome expression assay. The total mRNA expression of opioid receptors was higher in CXBH mice than in C57BL/6J and BALB/cBy mice. However, the expression levels of MOR-1 mRNA, a major transcript of the μ opioid receptor gene, were not different among the C57BL/6J, BALB/cBy, and CXBH strains. In conclusion, supraspinal nociceptive responses were reduced in the CXBH mouse strain, and the expression levels of transcripts were altered in the brain of this strain.

Bilateral sagittal split ramus osteotomy (BSSRO) is a common orthognatic surgical procedure. Sensory disturbances in the inferior alveolar nerve, including hypoesthesia and dysesthesia, are frequently observed after BSSRO, even without distinct nerve injury. The mechanisms that underlie individual differences in the vulnerability to sensory disturbances have not yet been elucidated.

Sphingomyelin synthase 1 (SMS1) catalyzes the conversion of ceramide to sphingomyelin. Here, we found that SMS1 null mice showed lipodystrophic phenotype. Mutant mice showed up-regulation of plasma triglyceride concentrations accompanied by reduction of white adipose tissue (WAT) as they aged. Lipoprotein lipase (LPL) activity was severely reduced in mutant mice. In vivo analysis indicated that fatty acid uptake in WAT but not in liver decreased in SMS1 null compared to wild-type mice. In vitro analysis using cultured cell revealed that SMS1 depletion reduced fatty acid uptake. Proteins extracted from WAT of mutant mice were severely modified by oxidative stress, and up-regulation of mRNAs related to apoptosis, redox adjustment, mitochondrial stress response and mitochondrial biogenesis was observed. ATP content of WAT was reduced in SMS1 null mice. Blue native gel analysis indicated that accumulation of mitochondrial respiratory chain complexes was reduced. These results suggest that WAT of SMS1 null mice is severely damaged by oxidative stress and barely functional. Indeed, mutant mice treated with the anti-oxidant N-acetyl cysteine (NAC) showed partial recovery of lipodystrophic phenotypes together with normalized plasma triglyceride concentrations. Altogether, our data suggest that SMS1 is crucial to control oxidative stress in order to maintain WAT function.

This prospective, randomized, controlled, rater-blinded study investigated the effect of G protein-activated inwardly rectifying potassium (GIRK) channel inhibitor ifenprodil on alcohol use in patients with alcohol dependence.

Reelin is a secreted protein essential for the development and function of the mammalian brain. The receptors for Reelin, apolipoprotein E receptor 2 and very low-density lipoprotein receptor, belong to the low-density lipoprotein receptor family, but it is not known whether Reelin is involved in the brain lipid metabolism. In the present study, we performed lipidomic analysis of the cerebral cortex of wild-type and Reelin-deficient (reeler) mice, and found that reeler mice exhibited several compositional changes in phospholipids. First, the ratio of phospholipids containing one saturated fatty acid (FA) and one docosahexaenoic acid (DHA) or arachidonic acid (ARA) decreased. Secondly, the ratio of phospholipids containing one monounsaturated FA (MUFA) and one DHA or ARA increased. Thirdly, the ratio of phospholipids containing 5,8,11-eicosatrienoic acid, or Mead acid (MA), increased. Finally, the expression of stearoyl-CoA desaturase-1 (SCD-1) increased. As the increase of MA is seen as an index of polyunsaturated FA (PUFA) deficiency, and the expression of SCD-1 is suppressed by PUFA, these results strongly suggest that the loss of Reelin leads to PUFA deficiency. Hence, MUFA and MA are synthesized in response to this deficiency, in part by inducing SCD-1 expression. This is the first report of changes of FA composition in the reeler mouse brain and provides a basis for further investigating the new role of Reelin in the development and function of the brain.

GPRC5B is a membrane glycoprotein robustly expressed in mouse cerebellar Purkinje cells (PCs). Its function is unknown. In Gprc5b-/- mice that lack GPRC5B, PCs develop distal axonal swellings in deep cerebellar nuclei (DCN). Numerous misshapen mitochondria, which generated excessive amounts of reactive oxygen species (ROS), accumulated in these distal axonal swellings. In primary cell cultures of Gprc5b-/- PCs, pharmacological reduction of ROS prevented the appearance of such swellings. To examine the physiological role of GPRC5B in PCs, we analyzed cerebellar synaptic transmission and cerebellum-dependent motor learning in Gprc5b-/- mice. Patch-clamp recordings in cerebellum slices in vitro revealed that the induction of long-term depression (LTD) at parallel fiber-PC synapses was normal in adult Gprc5b-/- mice, whereas the induction of long-term potentiation (LTP) at mossy fiber-DCN neuron synapses was attenuated in juvenile Gprc5b-/- mice. In Gprc5b-/- mice, long-term motor learning was impaired in both the rotarod test and the horizontal optokinetic response eye movement (HOKR) test. These observations suggest that GPRC5B plays not only an important role in the development of distal axons of PCs and formation of synapses with DCN neurons, but also in the synaptic plasticity that underlies long-term motor learning.

G protein-activated inwardly rectifying potassium (GIRK) channels are related to rewarding effects of addictive drugs. The GIRK2 subunit is thought to play key roles in the reward system. Weaver mutant mice exhibit abnormal GIRK2 function and different behaviors that are caused by several addictive substances compared with wild-type mice. However, mechanisms of reward-related alterations in weaver mutant mice remain unclear. The present study investigated changes in the rewarding effects of methamphetamine (METH) in weaver mutant mice.

5-Methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT) is a synthetic orally active hallucinogenic tryptamine analogue. The present study examined whether the effects of 5-MeO-DIPT involve the serotonin transporter (SERT) and serotonin 5-hydroxytryptamine-1A (5-HT1A ) receptor in the striatum and prefrontal cortex (PFC).

Patients with schizophrenia display characteristic smoking-related behaviors and genetic correlations between smoking behaviors and schizophrenia have been identified in European individuals. However, the genetic etiology of the association remains to be clarified. The present study investigated transethnic genetic overlaps between European-based smoking behaviors and the risk of Japanese schizophrenia by conducting polygenic risk score (PRS) analyses. Large-scale European genome-wide association study (GWAS) datasets (n = 24,114-74,035) related to four smoking-related intermediate phenotypes [(i) smoking initiation, (ii) age at smoking initiation, (iii) smoking quantity, and (iv) smoking cessation] were utilized as discovery samples. PRSs derived from these discovery GWASs were calculated for 332 Japanese subjects [schizophrenia patients, their unaffected first-degree relatives (FRs), and healthy controls (HCs)] as a target sample. Based on GWASs of European smoking phenotypes, we investigated the effects of PRSs on smoking phenotypes and the risk of schizophrenia in the Japanese population. Of the four smoking-related behaviors, the PRSs for age at smoking initiation in Europeans significantly predicted the age at smoking initiation (R2 = 0.049, p = 0.026) and the PRSs for smoking cessation significantly predicted the smoking cessation (R2 = 0.092, p = 0.027) in Japanese ever-smokers. Furthermore, the PRSs related to age at smoking initiation in Europeans were higher in Japanese schizophrenia patients than in the HCs and those of the FRs were intermediate between those of patients with schizophrenia and those of the HCs (R2 = 0.015, p = 0.015). In our target subjects, patients with schizophrenia had a higher mean age at smoking initiation (p = 0.018) and rate of daily smoking initiation after age 20 years (p = 0.023) compared with the HCs. A total of 60.6% of the patients started to smoke before the onset of schizophrenia. These findings suggest that genetic factors affecting late smoking initiation are associated with the risk of schizophrenia.

The genetic etiology of schizophrenia (SCZ) overlaps with that of other major psychiatric disorders in samples of European ancestry. The present study investigated transethnic polygenetic features shared between Japanese SCZ or their unaffected first-degree relatives and European patients with major psychiatric disorders by conducting polygenic risk score (PRS) analyses.

Epidermal growth factor (EGF) domain-specific O-GlcNAc transferase (EOGT) is an endoplasmic reticulum (ER)-resident protein that modifies EGF repeats of Notch receptors and thereby regulates Delta-like ligand-mediated Notch signaling. Several EOGT mutations that may affect putative N-glycosylation consensus sites are recorded in the cancer database, but the presence and function of N-glycans in EOGT have not yet been characterized. Here, we identified N-glycosylation sites in mouse EOGT and elucidated their molecular functions. Three predicted N-glycosylation consensus sequences on EOGT are highly conserved among mammalian species. Within these sites, we found that Asn-263 and Asn-354, but not Asn-493, are modified with N-glycans. Lectin blotting, endoglycosidase H digestion, and MS analysis revealed that both residues are modified with oligomannose N-glycans. Loss of an individual N-glycan on EOGT did not affect its endoplasmic reticulum (ER) localization, enzyme activity, and ability to O-GlcNAcylate Notch1 in HEK293T cells. However, simultaneous substitution of both N-glycosylation sites affected both EOGT maturation and expression levels without an apparent change in enzymatic activity, suggesting that N-glycosylation at a single site is sufficient for EOGT maturation and expression. Accordingly, a decrease in O-GlcNAc stoichiometry was observed in Notch1 co-expressed with an N263Q/N354Q variant compared with WT EOGT. Moreover, the N263Q/N354Q variant exhibited altered subcellular distribution within the ER in HEK293T cells, indicating that N-glycosylation of EOGT is required for its ER localization at the cell periphery. These results suggest critical roles of N-glycans in sustaining O-GlcNAc transferase function both by maintaining EOGT levels and by ensuring its proper subcellular localization in the ER.

Adiponectin is an adipose tissue-derived cytokine that exerts its antiinflammatory effects by binding to 2 adiponectin receptors, adiponectin receptor 1 (ADIPOR1) and adiponectin receptor 2 (ADIPOR2). However, the role of these adiponectin receptors on inflammatory pain remains unclear. We investigated the association between single nucleotide polymorphisms (SNPs) of these genes and inflammatory pain, such as postoperative pain and cancer pain.We analyzed 17 SNPs of the ADIPOR1 gene and 27 SNPs of the ADIPOR2 gene in 56 adult patients with postlaparotomy pain. We compared these genotypes with pain intensity and opioid consumption, adjusting for multiple testing. We analyzed the genotypes of 88 patients with cancer pain and examined the association of the relevant SNP(s) with pain intensity and opioid consumption.One variant of the ADIPOR1 gene (rs12045862) showed significant association with postoperative pain intensity; patients with minor allele homozygote (n = 7) demonstrated significantly worse pain intensity than that of combined patient group exhibiting major allele homozygote or the heterozygote (n = 49; Mann-Whitney test, P < .00002), although their opioid consumptions were comparable. Cancer pain intensity between minor allele homozygote patients (n = 7) and other 2 genotype patients (n = 81) were comparable.The rs12045862 SNP of the ADIPOR1 gene was associated with postoperative pain but not cancer pain. This might result from functional alteration of the ADIPOR1 signalling pathways, which influence the inflammatory process. ADIPOR1 may be a novel potential target for developing analgesics of postoperative pain.

Electroconvulsive therapy (ECT) has been applied for chronic pain for decades. The amounts of opioids to treat pain are sometimes reduced after a series of ECT. The effect of ECT on morphine-induced analgesia and its mechanism underlying the reduction of morphine requirement has yet to be clarified. Therefore, we administered electroconvulsive shocks (ECS) to mice and investigated the antinociceptive effect of morphine in a hot plate test. We examined the expression level of µ-opioid receptor in the thalami of mice 25 h after administration of ECS compared to the thalami of mice without ECS administration using western blotting. ECS disturbed the development of a decrease in the percentage of maximal possible effect (%MPE), which was observed 24 h after a morphine injection, when ECS was applied 25, 23, 21, and 12 h before the second administration of morphine. We also examined the effect of ECS on the dose-response curve of %MPE to morphine-antinociception. Twenty-five hours after ECS, the dose-response curve was shifted to the left, and the EC50 of morphine given to ECS-pretreated mice decreased by 30.1% compared to the mice that were not pretreated with ECS. We also found that the expression level of µ-opioid receptors was significantly increased after ECS administration. These results confirm previous clinical reports showing that ECT decreased the required dose of opioids in neuropathic pain patients and suggest the hypothesis that this effect of ECT works through the thalamus.

No effective pharmacological interventions have been developed for patients with methamphetamine use disorder. Ifenprodil is a blocker of G protein-activated inwardly rectifying potassium channels, which play a key role in the mechanism of action of addictive substances. We conducted a randomized, double-blind, exploratory, dose-ranging, placebo-controlled trial to examine the clinical efficacy of ifenprodil for the treatment of methamphetamine use disorder.

Dopamine-deficient (DD) mice exhibit psychomotor hyperactivity that might be related to a decrease in muscarinic signaling. In the present study, muscarinic acetylcholine receptor M2 (CHRM2) density decreased in the cortex in DD mice. This is significant because cortical CHRM2 acts as an autoreceptor; therefore, changes in CHRM2 levels could alter acetylcholine in DD mice. We also found that the CHRM1/CHRM4 agonist xanomeline and CHRM2 agonist arecaidine propargyl ester tosylate inhibited hyperactivity in DD mice, suggesting that postsynaptic CHRM1 and CHRM2 and presynaptic CHRM2 may be involved in hyperactivity in DD mice.