TOP一般演題(ポスター)
 
一般演題(ポスター)
Mood Disorders・Stress・Epilepsy
1P-48
Development of a novel method for assessing motivation in male mice
Hasebe Shigeru1,Ago Yukio2,Oka Satoshi2,Onaka Yusuke2,Hashimoto Hitoshi2,3,Matsuda Toshio4,Takuma Kazuhiro1,3
1Dept. Pharmacol., Grad. Sch. Dent., Osaka Univ.,2Lab. Mol. Neuropharmacol., Grad. Sch. Pharmaceut. Sci., Osaka Univ.,3United Grad. Sch. Child Dev., Osaka Univ. Kanazawa Univ. Hamamatsu Univ. Sch. Med. Chiba Univ. & Univ.Fukui,4Lab. Med. Pharmacol., Grad. Sch. Pharmceut. Sci., Osaka Univ.

Anhedonia is frequently observed in patients with psychiatric disorders. Sucrose preference is widely used as an index of motivation in rodents. However, previous studies show a strain difference in sucrose preference in mice. Here, we demonstrate a novel method for assessing motivation based on sexual orientation in mice. Six strains of mice, CD-1, ddY, BALB/c C57BL/6J, DBA/2J and C3H/HeJ mice, were purchased and used at 3 to 40 weeks of age. The test apparatus consists of three open chambers. Each male subject was habituated in the apparatus, and then two encountered mice, one female and one male, were introduced into wire-mesh boxes in the left and right chambers, respectively. The time the subjects spent in these two areas was measured for 10 min. All strains of mice showed a significant preference for female encounter regardless of its estrus cycle. The significant preference was observed repeatedly from 7 to 30 weeks old. The preference disappeared in castrated test mice. In addition, the preference was not observed in mouse models of depression such as isolation-reared, lipopolysaccharide(LPS)-treated and corticosterone-treated mice. Fluvoxamine improved the impaired preference in isolation-reared and LPS-treated mice. The metabotropic glutamate 2/3 receptor antagonist LY341495 had an antidepressant-like activity and improved the impaired preference in corticosterone-treated mice. The encounter to a female, but not male, mouse caused an increase in c-Fos expression in the nucleus accumbens shell of test male mice. In addition, dopamine D1 and D2 receptor antagonists blocked both the preference and increased c-Fos expression. These findings indicate that the novel method female encounter test can measure easily motivation in adult male mice.
1P-49
Antidepressant-like effect of resolvin E2 against lipopolysaccharide-induced depression-like behavior in mice
Shimoda Kento1,Deyama Satoshi1,Ide Soichiro1,Fukuda Hayato2,Shuto Satoshi2,Minami Masabumi1
1Dept. Pharmacol.,Grad. Sch. Pharm. Sci., Hokkaido Univ.,2Dept. Organic Chemistry for Drug Development.,Grad. Sch. Pharm. Sci., Hokkaido Univ.

Epidemiological studies suggest that dietary deficiency of n-3 polyunsaturated fatty acids(n-3 PUFA), such as eicosapentaenoic acid(EPA)and docosahexaenoic acid, is correlated to the prevalence of depression and that a chronic supplementation with n-3 PUFA exerts antidepressant-like effects. However, little is known about the underlying mechanisms. In this study, we examined whether resolvin E2(RvE2), one of the mediators generated from EPA, exerts antidepressant-like effect against lipopolysaccharide(LPS)-induced depression-like behavior. A tail suspension test(TST)was carried out 24 h after intraperitoneal administration of LPS(0.80 mg/kg)in male BALB/c mice. LPS challenge increased in immobility in the TST, an index of behavioral despair, which was dose-dependently reversed by intracerebroventricular(i.c.v.)injection of RvE2(1 or 10 ng)2 h before the TST. As RvE2 is reported to act on chemerin receptor 23(ChemR23)as a partial agonist and leukotriene B4 receptor BLT1 as an antagonist, we next examined which receptors are involved in antidepressant-like effect of RvE2. LPS-induced increase in immobility was dose-dependently reversed by i.c.v. injection of ChemR23 agonist peptide chemerin(50 or 500 ng), but not by the BLT1 antagonist U75302(10 or 50 ng). Last, we examined whether LPS challenge itself or combination with i.c.v. injection of RvE2, chemerin or U75302 alter locomotor activity. LPS and these treatments did not alter locomotor activity. Taken together, the present findings indicate that RvE2 exerts antidepressant-like effect via ChemR23, but not BLT1.
1P-50
Antidepressants via nitric oxide system -A pilot study in acute depressive model with arginine.
Yoshino Yuta,Kitano Tomoji,Nakata Shunsuke,Ochi Shinichiro,Ueno Shu-ichi
Department of Neuropsychiatry, Ehime University Graduate School of Medicine

Nitric oxide(NO)may be one of neurotransmitters related to Major Depressive Disorder(MDD)because a selective neuronal NO synthase(NOS)inhibitor, 7-nitroindazole, induces dose-dependent antidepressant-like effects. However, its role in MDD is not known yet. The purpose of the study is whether antidepressants improve depression via NO pathway using an acute depressive rat model with L-arginine(AR). We used three different types of antidepressants:fluoxetine(FLX, 10 mg/kg), milnacipran(MIL, 30 mg/kg), and mirtazapine(MIR, 10 mg/kg), in the depressive model using AR(750 mg/kg)pretreatment. We analyzed the mRNA expression levels of three NOS with real-time PCR method and serum NO levels. There are significant increases in the mRNA expression levels of the iNOS gene in brain regions after AR treatment although those of the eNOS gene tended to decrease with AR injection. After antidepressant treatments, there were no mRNA expressional changes in either nNOS or iNOS. However, the eNOS mRNA expression were significantly increased with FLX(cerebellum:P=0.011, hippocampus:P=0.011, midbrain:P=0.011, pons:P=0.013, striatum:P=0.011, thalamus:P<0.001). There was a statistically significant increase of serum NO levels with MIL(P=0.011). We conclude that changes of both eNOS mRNA level in the brain with FLX and the amount of serum NO with MIL may be related to their antidepressive effects of both agents but further experiments will be needed to ensure the involvement of NO system in MDD.
1P-51
Search for the blood-based biomarkers of late-onset major depressive disorder from the patients and the model mice
Mikuni Masahiko,Miyata Shigeo,Sakurai Noriko,Fukuda Masato
Department of Psychiatry and Neuroscience, Gunma University

The current diagnosis of major depressive disorder(MDD)is based on the evaluation of symptoms and relies on clinical interview. Use of MDD biomarkers will aid the accurate diagnosis, disease classification, and outcome evaluation of MDD treatment. To date, however, the biomarker which is accepted and available worldwide is nothing, and the discovery is strongly desired. Here we identified the state-dependent biomarkers in late-onset MDD(LOD)patients from the gene expression patterns of blood cells by cross-matching with the gene expression patterns in the blood cells of the model mice of postmenopausal depression, ovariectomized(OVX)mice with exposure to the chronic ultra-mild stress(CUMS). This study was performed in accordance with the Helsinki Declaration, as revised in 1989, and was approved by the Institutional Review Board of the Gunma University Hospital. All the participants received complete information on this study and signed an informed consent document. The mRNA levels of cell death-inducing DFFA-like effector c(CIDEC), ribonuclease 1(RNASE1), solute carrier family 36 member-1(SLC36A1), and serine/threonine/tyrosine interacting-like 1(STYXL1)differentiated depressed from non-depressed states in patients with LOD. The expression levels of these genes were significantly correlated with the severity of depression measured by the Structured Interview Guide for the Hamilton Depression rating scale. Of these, the mRNA level of Slc36a1 in the blood cells was also an objective index for identifying the depressive state-like blood condition in OVX+CUMS mice. These blood biomarkers will be helpful for properly diagnosing LOD and bridging the gap between animal studies and human clinical trials.
1P-52
MicroRNA normalizes glucocorticoid receptor levels in neuron and oligodendrocytes after stress exposure
Miyata Shingo,Shimizu Shoko,Tanaka Takashi,Tohyama Masaya
Div Mol Brain Sci, Res Ins Tra Asian Med, Kinki Univ

Major depressive disorder is one of the leading causes of disturbances in emotional, cognitive, autonomic, and endocrine functions, affecting nearly 7% of the population in Japan. According to the large amount of information on depressive diseases that has been accumulated during recent years, patients with major depressive disorder show an enhanced biologic stress-response mechanism, especially a hyperactive hypothalamic-pituitary-adrenal(HPA)axis and high levels of circulating cortisol. Although dysregulation of the HPA axis by chronic stress is indicative of major depressive disorder, the molecular mechanisms and functional changes in the brain underlying depression are largely unknown. It is well known that glucocorticoid receptor(GR)signaling regulates the hypothalamic-pituitary-adrenal(HPA)axis and GR expression level is associated with HPA axis activity. MicroRNAs(miRs)are noncoding RNAs that inhibit the translation and/or decrease the stability of their target mRNAs, ultimately decreasing their proteins expression. A previous report suggested that GR protein levels might be regulated by microRNA(miR)-18 and/or -124a in the brain. Furthermore, the Kampo medicine Yokukansan can affect psychological symptoms such as depression and anxiety that are associated with stress responses.Recently, we reported that stressed mice with elevated plasma levels of corticosterone exhibit morphological changes in the oligodendrocytes of nerve fiber bundles, such as those in the corpus callosum. However, little is known about the molecular mechanism of GR expression regulation in the oligodendrocytes after stress exposure.In this study, by using water-immersion and restraint stress as a stressor for mice, we attempted to elucidate the GR regulation mechanism in the paraventricular nucleus(PVN)of the hypothalamus and in the oligodendrocytes of corpus callosum, and evaluate the effects of Yokukansan on GR protein level regulation.
1P-53
Influence of aminergic modulation and stress on kainic acid-induced neuronal oscillations in anterior cingulated cortex
Shinozaki Rina1,Hashizume Miki1,Mukai Hideo2,Murakoshi Takayuki1
1Department of Biochemistry, Faculty of Medicine, Saitama Medical University,2Department of Computer Science, School of Science and Technology, Meiji University

Neuronal oscillation is a prominent form of rhythmic activity occurring in the brain. Fast neuronal oscillations(30-100Hz)are frequently observed in the thalamo-cortical structures when an animal is awake or attentive state. Abnormalities in these oscillations in the anterior cingulated cortex(ACC), a medial part of the prefrontal cortex, might underlie neuropsychiatric illnesses such as schizophrenia. Furthermore adjustment of these oscillatory activities by amine systems, such as VTA and basal forebrain, also plays an important role in higher brain function of the prefrontal cortex including ACC. We developed an in vitro model of neuronal oscillation in coronal slice preparation from young adult mice. In the current study, to elucidate physiological significance of ACC oscillation and its correlation with behavior, we first investigated the effects of aminergic modulation, and then examined influence of the stress on animal behaviors and the neuronal oscillation in the ACC.We performed extracellular field recording from layer 2/3 in cg1 regions in bilateral ACC and evoked neuronal oscillation by perfusing 1 or 3 μM kainic acid(KA)for 1 minute. This manipulation induced oscillatory activity with various frequency bands:θ(5-10 Hz);α(10-15 Hz);β(15-30 Hz);low-γ(30-50 Hz)and high-γ(50-80 Hz). These activities were evaluated by power-spectral density analysis. Dopamine(DA, 10μM)and noradrenaline(NA, 10μM)were administered by perfusion for 10 min before KA activation. These amines increased oscillation power evoked by kainic acid depending on the frequency ranges. We will report the correlation of aminergic action on the oscillation power and stress-induced behavioral changes.
1P-54
Contrasting feature of ERK1/2 activation and synapsin I phosphorylation at the ERK1/2-dependent site in the rat brain during epileptic seizure activity in vivo
Yamagata Yoko1,2,Nairn Angus C.3,4,Obata Kunihiko1,Imoto Keiji1,2
1Natl Inst for Physiol Sci,2SOKENDAI,3Yale Univ,4Rockefeller Univ

Extracellular signal-regulated kinase 1/2(ERK1/2)that belongs to a subfamily of mitogen-activated protein kinases(MAPKs)plays diverse roles in the central nervous system. There have been a number of studies showing activation of ERK1/2 in various types of seizure activity in vivo and in vitro, but few studies have been conducted to examine the relationship between ERK1/2 activation and its substrate phosphorylation in seizure models. We have been studying the phosphorylation state of a presynaptic protein, synapsin I at ERK1/2-dependent and -independent sites in various types of seizure models, i.e., a cortical slice model of seizure activity and electroconvulsive treatment-induced seizure activity in rats in vivo. Here in this study, we examined the effects of prolonged seizure activity on ERK1/2 activity and synapsin I phosphorylation by using status epilepticus induced by kainic acid(KA-SE)in rats in vivo. In KA-SE, robust ERK1/2 activation was observed in the hippocampus, a representative limbic structure, and lesser activation in the parietal portion of the cerebral cortex, a representative non-limbic structure. On the other hand, the phosphorylation level of synapsin I at ERK1/2-dependent phospho-site 4/5 was profoundly decreased, the extent of which was much larger in the hippocampus than in the parietal cortex. Based on the present and previous results, we will discuss the relationship between neuronal excitation, ERK1/2 and phosphatase activities, and phosphorylation state of synapsin I in vivo.
1P-55
BRINP expressions in pentylenetetrazol-kindled mice
Kobayashi Miwako1,Asakawa Hanako1,Kono Yasuhiro1,Waki Sayaka1,Takechi Kenshi2,Tanaka Akihiro2,Araki Hiroaki2,Matsuoka Ichro1
1Col. of Pharm. Sci., Matsuyama Univ.,2Division of Pharmacy, Ehime University Hospital

BRINP(BMP/RA-inducible neural-specific protein)-1, 2, 3 are family genes that are specifically expressed in the nervous system. Among the three family members, BRINP1 is most highly expressed in various brain regions including hippocampus, and its expression is further up-regulated in dentate gyrus(DG)by intraperitoneal(i.p.)administration of kainic acid. Each BRINP possesses an ability to suppress cell cycle progression in cultured neural stem cells, and disruption of BRINP1 by homologous recombination led to the increase in the neurogenesis in subgranular zone of adult mice(BRINP1-KO mice). Furthermore, BRINP1-KO mice exhibited abnormal behaviors with an increase in locomotor activity, reduced anxiety-like behavior, poor social interaction and slight impairment of working memory, which are relevant to symptoms of human psychiatric disorders such as schizophrenia and ADHD. In this study, we examined BRINP expressions in pentylenetetrazol(PTZ)-kindled mice as an epileptic model. Kindling was induced by i.p. injection of 35 mg/kg PTZ into C57BL/6J male mice every 48 hrs. PTZ-kindled mice exhibited no impaired working memory in Y-maze test, but they showed hyperactivity as indicated by the increases of the total number of arm entries and the number of rearing actions. Expression levels of BRINP-mRNAs in hippocampus of the PTZ-kindled mice at steady state are the same as those in control mice. On the other hand, BRINP1-mRNA expression as well as that of BDNF-mRNA was increased in hippocampus of the kindled mice 3hrs after reinjection of PTZ. We also examined induction of neuronal death by the PTZ-exposure to organotypic hippocampal slice culture. Increased fluorescence of propidium iodide(PI)incorporated into dead neurons was detected in dentate granular cells and CA3 pyramidal neurons from 1 day after PTZ exposure and in CA1 pyramidal neurons at later periods.These results suggest that BRINP1 expression is regulated in an activity dependent manner in PTZ-kindled mice. DG and CA3 neurons are more sensitive to PTZ-induced excitotoxicity than CA1 pyramidal neurons.
1P-56
The basic mechanisms underlying ketogenic diet:a neuronal autocrine regulation through adenosine receptor
Kawamura Masahito
Dept. Pharmacol., Jikei. Univ. Sch. Med.

A ketogenic diet(a low-carbohydrate high-fat protocol)was designed in the 1920s to mimic fasting and it has been used successfully to treat pediatric and medically-refractory epilepsy. Despite decades of clinical use, the neural mechanisms underlying the anticonvulsant effects of a ketogenic diet are not well understood. To elucidate this, we fed rats a ketogenic or control diet for 2-3 weeks, prepared acute hippocampal slices, and performed electrophysiology and pharmacology in the seizure-prone CA3 region. In slices prepared from ketogenic diet-fed animals we found reduced excitability and seizure propensity. Similar to clinical observations, reduced excitation depended on maintaining reduced glucose;changes reversed rapidly when glucose was increased. We found decreased excitability depended on increased pannexin-1 channel, adenosine A1 receptor and KATP channel activation, thus identifying specific mechanisms influencing neuronal activity. These results suggest that the reduction of neuronal activity through activation of adenosine A1 receptor via purinergic autocrine regulation is one of the key mechanisms underlying anticonvulsant effects of ketogenic diet.