一般演題（ポスター）

一般演題（ポスター） Late-breaking Abstracts (LBA)

3P-53 Glycine transporter inhibitors relieve bone cancer pain Dohi Toshihiro¹，Morita Katsuya²，Motoyama Naoyo³，Shiraishi Seiji⁴ ¹Pharmaceutical Sci. Nihon Pharmaceutical Univ. Saitama，²Dept of Pharmacol, Faculty of Nursing, Hiroshima Bunka Gakuen Univ, Hioshima，³Dept of Dental Sci for Health Promotion, Institute of Biomed & Health Sci, Hiroshima Univ, ，⁴Cancer Pathophysiol, Div Natl Cancer Center Research Institute Bone cancer gives rise to the most severe pain according to complex mechanisms in which a neuropathic element is included. Bone cancer pain often resistants to conventional analgesics and thus novel medicament for bone cancer pain is desired. Recent studies have revealed the anti-nociceptive effects of glycine transporter (GlyT) inhibitors in neuropathic pain models such as sciatic nerve injured and diabetic animals. In the present study the effects of GlyT inhibitors on bone cancer pain were examined in animal model. For the bone cancer (FBC) model, NCTC 2472 tumor cells were injected into the medullary cavity of the distal femur of C3H/HeN mice. Pain Behaviors such as allodynia, withdrawal threshold, guarding behavior and limb-use abnormality were assessed at 11 days post tumor transplantation. GlyT2 inhibitors, ORG 25543 and ALX 1393, and GlyT1 inhibitor ORG 25935 by intravenous or oral administration improved all of the pain-like behaviors. Knockdown of the expression of spinal GlyTs protein by intrathecal injection of siRNA of GlyT mRNA also improved the pain-like behaviors. The pain-relief activity was potent and long lasting. However, injection of ORG 25543 on the 2nd day post tumor implantation caused three phases of pain responses; pain-like behaviors were initially accelerated (at 2-4 days) and subsequently almost disappeared (5-7 days) and then reappeared. Intrathecal injection of strychnine at 1 day after injection of ORG 25543 transiently antagonized to the pain-acceleration of ORG 25543. In control mice, strychnine improved pain-like behaviors at 4 days post tumor implantation and aggravated between 4 and 5 days. The evidence suggests that the different mechanisms are phase-dependently involved. GlyT inhibitors may represent a new strategy for the treatment of bone cancer pain and also help to investigate further the mechanisms underlying development of bone cancer pain.		3P-54 Mechanism of non-enzymatic activation of Factor XIII-A in zebrafish retina and optic nerve after optic nerve injury Sugitani Kayo¹，Koriyama Yoshiki²，Ogai Kazuhiro³，Kato Satoru^3,4 ¹Dept Clinical Laboratory Sci., Grad. Sch. Med. Sci., Kanazawa Univ.，²Grad. Sch. Pharm Sci, Suzuka University of Med Sci，³Wellness Promotion Science Center, Institute of Medical, Pharmaceutical and Health Sci., Kanazawa Univ., ，⁴Dept. Mol. Neurobiol., Grad. Sch. Med. Sci., Kanazawa Univ. Unlike mammals, fish central nervous system (CNS) neurons can regrow their axons and restore their function even after optic nerve transection. Therefore, the fish visual system has been used as a CNS nerve regeneration model. In the process of fish optic nerve regeneration, a large number of genes are upregulated as regeneration-associated molecules. Using molecular cloning techniques, we identified Factor XIII-A (FXIII-A) as one of upregulation genes in the zebrafish visual system after optic nerve injury. FXIII was originally identified as a plasma transglutaminase consisting of two catalytic A subunits (FXIII-A) and two non-catalytic B subunits. It promotes clot stabilization by catalyzing the formation of covalent cross-linking reactions in polymerized fibrin as a blood coagulation factor. FXIII-A is activated by thrombin to cleave the activation peptide on the N-terminus of the A subunit. We detected the activation of FXIII-A in astrocytes/microglial cells in the optic nerve at the crush site and retinal ganglion cells after optic nerve injury. However, there are no thrombin expression in retina and optic nerve. To elucidate the mechanism of FXIII-A activation in the absence of thrombin after optic nerve injury, we compared the expression pattern of FXIII-A divided into two regions. One is the region containing activation peptide that is cleaved by thrombin, and the other is the region containing active site of FXIII-A. As a result, only the region containing the active site of FXIII-A, was markedly increased after optic nerve injury. These results suggest that there are non-enzymatic activation mechanisms of Factor XIII-A in zebrafish retina and optic nerve after optic nerve injury.

3P-55 Acute hypoxia increases mitochondrial DNA gene expression and complex I and IV enzyme activity in mouse brain slices Takanari Nakano，Shinozaki Rina，Ida Yui，Kotani Norihiro，Hashizume Miki，Murakoshi Takayuki Department of Biochemistry, Saitama Medical University Background: Constant ATP supply by mitochondria is a key to cell survival. Shortage or depletion of O₂ supply, such as under ischemic conditions, not only impairs the ATP production, but also generates reactive oxygen species, elicits subsequent inflammation, and induces apoptotic cell death. These can cause irreversible tissue damage and clinically severe conditions. Understanding the molecular cascades for hypoxia-induced inflammation and apoptosis will advance approaches to ameliorate permanent damage by ischemic stroke. Mitochondria play a crucial role in the cascades, but it is unclear how mitochondria respond to acute hypoxia. Mitochondrial DNA (mtDNA) is coding some key components of respiratory chain complex I and IV. We thus examined whether hypoxia alters the mtDNA gene expression and tried to detect corresponding changes in respiratory chain enzyme activity. Methods: Unlike cultured cells, acute brain slices retain active respiration, providing a physiologically-relevant material that enables precise interventions and biochemical analyses. To examine mtDNA gene expressions and respiratory chain activity, we prepared slices from mouse forebrains and let them recover for 1 hour under 95% O₂/5% CO₂ at room temperature. For hypoxic conditions (HC), the slices were then exposed to atmosphere (21% O₂) for 20 min. Results: ATP in the brain slices disappeared within 5 min under HC. We quantified mRNA species which are coded in mtDNA by RT-PCR analysis and found that, of the 11 mRNA species examined, 7 had more than 50% increase in the amount after HC. No apparent increase was observed in 8 mRNA species for mitochondrial proteins coded in the nuclear genome or 8 housekeeping gene expressions, suggesting specific induction for mtDNA expression. Corresponding to the increaesd mtDNA gene expressions, complex I and complex IV enzyme activity increased more than 50%, respectively. Conclusions: The results suggest that the mitochondria of the brain slices increase the respiratory chain ability via increased mtDNA gene expression when O₂ supply is limited. This response may be related to the cascades that deteriorate ischemic or reperfusion-induced tissue damage.		3P-56 A new animal model of psychiatric disorders caused by child abuse and involvement of orbitofrontal cortex in its behavioral abnormality Kuniishi Hiroshi¹，Ichisaka Satoshi²，Yamamoto Miki¹，Ikubo Natsuko³，Matsuda Sae¹，Futora Eri³，Harada Riho³，Kato Maiko²，Ishihara Kohei²，Hata Yoshio¹ ¹Div. Integrative Biosci., Tottori Univ. Grad. Sch. Med. Sci.,，²Div. Neurobiol., Sch. Life Sci., Fac. Med. Tottori Univ., ，³Div. Neurobiol., Tottori Univ., Grad. Sch. Med. Sci., Abused children have an increased risk for developing psychiatric disorders with high levels of trait impulsivity, aggression, and suicidal behavior. To develop a novel treatment for the psychiatric disorders, an animal model that shows behavioral changes like human is necessary. In our previous study, however, maternal-separation, early-deprivation, and post-weaning social isolation, which all are known as a rodent model of neglect, showed little behavioral effect. Hence, in the present study, we examined the effect of the combination of post-weaning social isolation rearing stress and post-weaning electric-foot-shock stress (PW-I+S) in rat. The PW-I+S rats showed behavioral changes after maturation, increased impulsive aggression and escape behavior from the environment with aversive memory in early life, and decreased social behaviors. These behavioral changes is similar to the psychiatric symptoms observed in abused children such as impulsive aggression, running away from home and social withdrawal, thus this model could be an animal model of the psychiatric disorders caused by child abuse. Furthermore, to investigate involvement of orbitofrontal cortex in these behavioral change, we determined whether pharmacological orbitofrontal inactivation affects impulsive aggression, escape behavior from the environment with aversive memory in early life and social behaviors. We found that the inactivation of orbitofrontal cortex increased impulsive aggression and prevented escape behavior from the environment with aversive memory in early life. These results suggest that early life stress could affect orbitofrontal neuronal circuit and lead to behavioral abnormality such as impulsive aggression and running away from home even after maturation.

3P-57 Cholinergic stimulation may protect hippocampal synaptic plasticity against the toxicity of synthesized Amyloid-Oligomer. Sato Toyohiro¹，Ohi Yoshiaki²，Haji Akira²，Matsukawa Noriyuki¹ ¹Dept. of Neurology, Nagoya City Univ. ，²Neuropharmacology, Aichi Gakuin Univ. The plasticity of hippocampal glutamatergic neurons, modulated by cholinergic neurons from medial septal nuclei (MSN), plays an important role for memory. In the early stage of Alzheimer disease, soluble amyloid oligomers may disturb hippocampal glutamatergic neuronal plasticity and exacerbate cognitive functions. We previously discovered a peptide, inducing acetylcholine synthesis in MSN, and named hippocampal cholinergic neurostimulating peptide (HCNP). While this peptide is cleaved from 186 amino-acids protein, HCNP precursor protein (HCNP-pp), we generated its transgenic (HCNP-pp Tg) mice.In this study, first to elucidate the modulating-mechanism of cholinergic regulation on glutamatergic neural activity in hippocampus, we investigated the relations between the numbers of preconditioning-tetanic stimuli (TS 100Hz 1sec) on Shaffer collateral and the enhancement of long-term potentiation (LTP) in the hippocampus of wild-type (WT) mice. As the results, the enhancement of LTP were amplified depending on the numbers of the TS and plateaued with twice TS. Secondly, we estimated the effect of cholinergic stimulation by charbachol (CCh 50nM) on LTP enhancement with each single or twice TS, and showed that CCh could amplified LTP only with single TS. Thirdly, the similar level enhancement of LTP with twice TS in WT mice was observed in the HCNP-pp Tg mice with single TS, indicative the effect of endogenous cholinergic stimulation. Finally, we estimated the protecting effect of cholinergic stimulation against the toxicity of synthesized soluble amyloid oligomers. In WT mice amyloid oligomers could suppress LTP with dose dependence, indicative of the toxic effect against glutamatergic neural plasticity. On the other hand, in HCNP-pp Tg mice could show a tendency to prevent LTP from the suppression by amyloid oligomers.In conclusion, cholinergic stimulation could modulate the synaptic plasticity of un-saturated hippocampal glutamatergic neural activity. In addition, endogenous cholinergic regulation by HCNP/HCNP-pp, could prevent the glutamatergic neural plasticity from the impairment by amyloid oligomers, suggesting protecting effect of cholinergic stimulation against amyloid oligomers toxicity.		3P-58 Ablation of neuropsin-neuregulin 1 signaling imbalances ErbB4 inhibitory networks and disrupts hippocampal gamma oscillation Morikawa Shota^1,2,3，Kawata Miho^2,3，Shiosaka Sadao³，Tamura Hideki¹ ¹Life Science Tokyo Advanced Research center (L-StaR), Hoshi University，²Dept. Pharmacol., Hoshi Univ. Sch. Pharm. Pharmaceut. Sci.，³Laboratory of Functional Neuroscience, Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST) Parvalbumin-expressing interneurons are pivotal for the processing of information in healthy brain, while the coordination of these functions is seriously disrupted in diseased brain. How these interneurons in the hippocampus participate in cognitive functions remains unclear. We previously reported that neuregulin 1 (NRG1)-ErbB4 signaling, which is actuated by neuropsin, is important for coordinating brain plasticity. Neuropsin cleaves mature NRG1 (bound to extracellular glycosaminoglycans) in response to long-term potentiation or depression, liberating a soluble ligand that activates its receptor, ErbB4. Here, we show in mice that kainate-induced epileptic seizures transiently elevate neuropsin's proteolytic activity and stimulate cFos expression with a time course suggesting that the activation of ErbB4- and parvalbumin-expressing interneurons follows the excitation and subsequent silencing of pyramidal neurons. In neuropsin-deficient mice, kainate administration impaired signaling and disrupted the excitation-inhibition balance (E/I balance), by decreasing the activity of parvalbumin-positive interneurons while increasing that of pyramidal neurons. Gamma oscillations in neuropsin-deficient mice had reduced power that was restored to normal levels by intracerebral infusion of soluble NRG1 ligand moiety. These results suggest that the neuropsin-NRG1 signaling system is a requisite for brain cognition and that neuropsin regulates E/I balance through NRG1-ErbB4 signaling toward parvalbumin-expressing interneurons. This neuronal system may be a useful target of pharmacological therapies against cognitive disorders.

3P-59（1P-21） Effect of histone deacetylase inhibitor on synaptic dysfunction elicited by X-irradiation Hiruma Takashi，Koganezawa Noriko，Puspitasari Anggraeini，Shirao Tomoaki Department of Neurobiology and Behavior, Gunma University Graduate School of Medicine Treatments for cancers have been developing surprisingly due to progresses of radiotherapy techniques. It has been known, however, that cranial irradiation causes cognitive deficits, although the underlie mechanism of such cognitive deficits is still remain unknown. We have been studying the effect of X-irradiation on neurons in vitro, and have reported that the density of dendritic spines was decreased or the changes in spine morphology by X-irradiation. Furthermore, using drebrin, an actin binding protein, as a marker for synaptic function, we found the number of drebrin clusters decreased transiently by X-irradiation. We have also shown that amyloid beta oligomers-induced change of drebrin accumulation is mediated by histone deacetylase (HDAC) (Ishizuka et al., 2014). And some of HDAC inhibitors are known to protect normal cells from radiation-induced damage. In this study we examined if the accumulation change of drebrin by X-irradiation is also mediated by HDAC, and tested the possibility of HDAC inhibitors usage as therapeutic tools to weaken irradiation effects on synaptic function. We used primary hippocampal cultured neurons and suberoylanilide hydroxamic acid (SAHA) as a HDAC inhibitor. Drebrin was used as a marker of synaptic function and a post synaptic marker and Synapsin I was used as a pre synaptic marker and these proteins were analyzed immunocytochemically. The cultured neurons were pretreated with SAHA 1 hour before irradiation and were fixed at 2, 8, and 24 hours after the irradiation. We evaluated the effect of SAHA by counting drebrin and Synapsin I clusters. Although the data was not significantly different due to the small sample number, it suggested that low dose of SAHA blocks the X-irradiation induced transient decrease of drebrin accumulation.