シナプス可塑性 Synaptic Plasticity
P3-2-1 シンタキシン1A-CaMKII相互作用によるシナプス短期可塑性の制御 Presynaptic Ca2+/calmodulin-dependent protein kinase II (CaMKII) regulates short-term plasticity through the interaction with syntaxin-1A ○渡邊裕美1,2,5, 片山憲和3, 武内恒成1,2, 崎村建司4, 真鍋俊也3, 五十嵐道弘1,2 ○Yumi Watanabe1,2,5, Norikazu Katayama3, Kosei Takeuchi1,2, Kenji Sakimura4, Toshiya Manabe3, Michihiro Igarashi1,2 新潟大・院・医歯学総合・分子細胞機能学1, 新潟大・超域学術院2, 東京大・医科研・神経ネットワーク3, 新潟大・脳研・細胞神経生物4, 日本学術振興会特別研究員（RPD）5 Div Mol Cell Biol, Grad Sch Med Dent Sci, Niigata Univ1, Trans-deciplinary Res Progr, Niigata Univ2, Div Neuro Net, Dept Basi Med Sci, Inst Med Sci, Univ Tokyo3, Dept Cell Neurobiol, Brain Res Inst, Niigata Univ4, JSPS Research Fellow (RPD)5 Ca 2+/calmodulin-dependent protein kinase II (CaMKII) is an important modulator of neural plasticity. CaMKII is a major protein component of presynaptic terminals as well as postsynaptic densities. We previously found that the autophosphorylated CaMKII interacts with syntaxin-1A, a t-SNARE operating the vesicle docking and fusion, in the presence of submicromolar Ca2+, and demonstrated at the cellular level that this binding modulates the frequency of exocytosis. This interaction is strongly dependent upon R151 of syntaxin-1A. Syntaxin-1A (R151G) lost its CaMKII-binding activity (J Neurosci, 2002; J Neurosci Res, 2003). We produced the knock-in (KI) mice having syntaxin-1A (R151G). Electrophysiological experiments using hippocampal slice culture revealed no significant change in the basal synaptic transmission in the KI, but with repetitive stimulation, abnormal presynaptic plasticity, showing the larger synaptic response, was found in the KI. Biochemically, CaMKII-syntaxin-1A interaction was severely reduced in the KI, while the amount of complexin bound to syntxin-1A also decreased. Although the effect of complexin on exocytosis is bidirectional, but it acts as a molecular clamp to the fusion and it should be inhibitory to fusion first. The enhanced short-term plasticity observed in the KI should result from the insufficient recruitment of complexin to the SNARE complex, caused by the disrupted interaction between CaMKII and syntaxin-1A. Together, these data suggested the importance of CaMKII-syntaxin-1A interaction in the following recruitment of complexin to the SNAREs, when the presynaptic plasticity is regulated.	P3-2-2 性成熟前後のマウスにおける海馬樹状突起スパインに対するテストステロンの影響 Effect of testosterone on alteration of hippocampal dendritic spines in sexually immature and mature mice ○鈴木惠雅1,2, 片倉智子3, 望月しのぶ3, 藤原宏子2,3, 佐藤亮平4, 齋藤理佳3, 宮本武典1,3 ○Ema Suzuki1,2, Satoko Katakura3, Shinobu Mochizuki3, Hiroko Eda-Fujiwara2,3, Ryohei Satoh4, Rika Saito3, Takenori Miyamoto1,3 日本女子大・院理・生体情報科学1, 日本学術振興会2, 日本女子大・理・生体情報科学3, 北里大・医・生理学4 Lab Behav Neurosci, Grad Sch Sci, Japan Women's Univ, Tokyo, Japan1, JSPS, Tokyo, Japan2, Dept Chem Biol Sci, Japan Women's Univ, Tokyo, Japan3, Dept Physiol, Sch Med, Kitasato Univ, Kanagawa, Japan4 In the gonadectomized adult male and female rats, it has been demonstrated that testosterone plays essential roles in the modulation of synaptic plasticity with remarkable increase of number of dendritic spines in the hippocampus, which is the center of the declarative memory such as the spatial memory. In the present study using the hippocampal slices of the C57BL/6 mice, we compared the effects of testosterone on the alteration of dendritic spines between sexually mature and immature mice. After a treatment with or without testosterone, the dendritic spines on hippocampal neurons in sexually mature or immature mice were visualized with Golgi staining and we measured the spine cross-section area, which reflects the number of dendritic spines. The treatment with testosterone increased the spine area in both sexually immature and mature mice, but no difference was observed between before and after sexual maturation. Our previous reports suggested that the exposure of testosterone at the sexual pre-maturation period enhances the retention of extinction memory of conditioned taste aversion (CTA). Therefore, we are trying to examine whether the similar effects of testosterone obtained in the hippocampal experiments could be observed in the amygdala or the ventral medial prefrontal cortex (vmPFC), which is the center of the nondeclarative memory such as the emotional memory including CTA or not.
P3-2-3 苔状線維－CA3間シナプスで繰り返し長期増強の誘発後に生起する可塑的変化 Plastic changes in the mossy fiber-CA3 pyramidal cell synapses after repetitive inductions of LTP: An in vitro study ○有賀理瑛1, 冨永-吉野恵子1, 小倉明彦1 ○Rie Ariga1, Keiko Tominaga-Yoshino1, Akihiko Ogura1 大阪大院・生命1 Frontier Biosciences, Osaka Univ, Osaka1 Long-term potentiation (LTP) in acute hippocampal slices is often regarded as the cellular basis of memory. However, those preparations are not suited best for analyzing memory of a day-to-week order. Using organotypic slice cultures of the hippocampus, we reported previously that three repetitive inductions LTP, but not a single induction, led to a slowly developing long-lasting synaptic enhancement coupled with new synapse formation in the Schaffer fiber-CA1 pathway (Tominaga-Yoshino et al. 2002, 2008) and named this phenomenon RISE (Repetitive LTP-Induced Synaptic Enhancement). It is important whether synaptic plasticity equivalent to RISE would occur in the mossy fiber-CA3 pathway, since the mechanism of LTP in this pathway is distinct and since this is an intermediate pathway in the neuronal circuit of the culture. A single treatment with FK (forskolin; adenylate cyclase activator) induced LTP in the mossy fiber-CA3 pathway. However, three repeated FK-exposures failed to produce a long-lasting synaptic enhancement. The density of thorny excrescences (thorn; postsynaptic structure) did not change, either. Then we prepared slice cultures with removed CA1 region (DG-CA3 cultures). In this preparation the CA3 pyramidal cells turned to show an increase in thorn density after 3 FK-exposures, showing that the mossy fiber-CA3 pathway also possesses the capability to evoke structural plasticity. Puzzlingly, however, the increase in synaptic strength did not increase in parallel with the structural changes. By a histochemical examination, the number of DG neurons increased in the DG-CA3 cultures after 3 FK-exposures, which may explain the apparent discrepancy between structure and function. As a tentative conclusion, the mossy fiber-CA3 pathway can express synaptic plasticity when it is the terminal of neuronal circuit, in a phenotype different from that of Schaffer fiber-CA1 pathway.	P3-2-4 慢性疼痛モデルマウス脊髄後角におけるCaMKIIのシナプス局在 Synaptic localization of CaMKII with mice model of chronic pain ○矢尾育子1, 松村伸治1, 伊藤誠二1 ○Ikuko Yao1, Shinji Matsumura1, Seiji Ito1 関西医科大学 医学部 医化学講座1 Dept Med Chem, Kansai Med Univ, Osaka1 Recently, evidence points to a key role for Ca2+/calmodulin-dependent protein kinase II (CaMKII) in nociceptive transmission. A major isoform CaMKII alpha is an essential mediator of activity-dependent synaptic plasticity or long-term potentiation (LTP), which can be triggered by N-methyl-d-aspartate (NMDA) receptor-mediated Ca2+ influx. CaMKII alpha is preferentially localized in pain-processing regions in the CNS such as lamina II of the spinal cord dorsal horn and the dorsal root ganglion (DRG). It is known that CaMKII is upregulated in the superficial laminae of the dorsal horn and the DRG cells after inflammation or injuries to peripheral tissues. In the present study, the localization of CaMKII in the superficial laminae of the dorsal horn of the chronic pain model mouse was investigated. The chronic pain model mice were prepared by L5 spinal nerve transection. One week after the surgery, the spinal cord of the model mice were fixed for pre-embedding immuno electron microscopy with Gold enhancement. Gold particles labeling CaMKII or the phosphorylated form on the laminae II-III were counted. The number of gold particles for CaMKII was upregulated in the spinal cord of treated mice. Moreover, the number of gold particles for phosphorylated form of CaMKII was increased especially near the postsynaptic membrane. Theses results suggest that the phosphorylation of CaMKII happens during the chronic pain and the phosphorylated CaMKII is recruited and localized at the synaptic sites.
P3-2-5 ホルマリン誘発炎症痛モデルにおける疼痛行動と侵害受容扁桃体シナプス増強の時間的乖離 Mechanism underlying synaptic potentiation of nociceptive amygdala in formalin-induced inflammatory pain model of rats ○宮沢祐太1, 杉本真理子1, 高橋由香里1, 加藤総夫1,2 ○Yuta Miyazawa1, Mariko Sugimoto1, Yukari Takahashi1, Fusao Kato1,2 慈恵医大・神経生理1, 名古屋大2 Lab Neurophysiol, Dept Neurosci, Jikei Univ Sch Med, Tokyo, Japan1, Nagoya Univ, Aichi, Japan2 Nociception is essentially linked with pain-induced negative emotion. The capsular part of the central amygdala (CeC) is one of the primary sites of such nociception-emotion link because it receives direct nociception-related inputs of spinal origin from the lateral parabrachial nucleus (LPB) and also is a member of the amygdalar emotion circuit. This nociception-emotion link at the CeC becomes potentiated as evidenced by potent synaptic potentiation at the LPB-CeC synapse in various semi-acute to chronic pain models (Ikeda et al., 2007; Nakao et al., 2012). However it remains unclear whether the spontaneous persistent nociception in these painful states is required in the establishment of such potentiation. To examine whether the time-course of nociception and such potentiation could be dissociated, we used acute formalin injection model because it shows rapid phasic changes in the pain/emotion behavior and also because a robust LPB-CeC potentiation is reported also with this model (Adedoyin et al., 2010). At 90 min after left intraplantar injection of 5% formalin solution in rats, spontaneous nociceptive behaviors such as licking, flinching, and lifting almost completely disappeared. At 6 hours after injection, at which mechanical allodynia at the left hindlimb ipsilateral to injection also disappeared, we made brain slice and found that the LPB-CeC synaptic transmission was significantly potentiated in the right amygdala, being accompanied by a significant decrease in paired-pulse ratio and by limited involvement of NMDA receptor component in the potentiation, unlike in the arthritic pain models at 6-8 hours (Bird et al., 2005). Altogether, it is suggested that LPB-CeC potentiation develops after initial nociceptive phase even without manifest persistent and spontaneous nociception thereafter through synaptic mechanisms distinct from models with on-going spontaneous nociception.	P3-2-6 時間的に異なる2つの感覚入力によって引き起こされるゼブラフィッシュ手綱核－脚間核間神経伝達の増強 Potentiation in habenulo-interpeduncular transmission evoked by two temporally different sensory inputs in zebrafish ○木下雅恵1, 岡本仁1 ○Masae Kinoshita1, Hitoshi Okamoto1 理化学研究所　脳科学総合研究センター　発生遺伝子制御研究チーム1 Laboratory for Developmental Gene Regulation, RIKEN Brain Science Institute1 Our previous studies showed that the inputs from the lateral subnucleus of dorsal habenula (dHbL) to the dorsal interpeduncualr nucleus (dIPN) is essential for the experience-dependent regulation of fear behavior, i.e. freezing v.s. flight, and that the dIPN is reciprocally connected with the central gray (CG) which contains the homologous region of the periaqueductal gray in zebrafish. These evidences suggest that fear behavior is regulated by the inputs to CG from the dIPN which is modulated by the dHbL-dIPN transmission. Here, we identified field excitatory postsynaptic potential (fEPSP) in the dIPN evoked by the dHbL stimulation in vivo, and monitored changes in the fEPSP caused from tetanic stimulation of dHbL and tail shock as a sensory input. Tetanic stimulation of dHbL did not affect fEPSP, except that it caused transient potentiation. The field potential in the dIPN evoked by tail shock alone was gradually increased in a shock strength dependent manner. Bilateral habenula excision did not affect the tail shock evoked potentials, indicating that pain signal inputs to the dIPN is not mediated by the habenula neurons. Simultaneous application of tetanic stimulation to the dHbL and tail shock caused only transient potentiation of fEPSP. However, 20-secoud delay of tail shock after tetanic stimulation of dHbL caused long-term potentiation of fEPSP. These data suggest that the plasticity in the dIPN induced by the temporally different two stimuli from dHbL and GC may be critical for the modulation of the experience-dependent fear behavior.
P3-2-7 海馬シナプス活動の随意的活性化 Volitional Activation of Hippocampal Synapses ○石川大介1,2, 松木則夫1, 池谷裕二1 ○Daisuke Ishikawa1,2, Norio Matsuki1, Yuji Ikegaya1 東京大院・薬・薬品作用1, 日本学術振興会　特別研究員（DC1）2 Dept Pharm, Univ of Tokyo, Tokyo1, Research fellow, Japan Society for the Promotion of Science, Tokyo2 Learning is a plastic adaptation of the neural circuit toward generating more preferable output. In a microscopic view, however, how the synaptic activities are patterned into desired configurations is still unknown. To address this question, we employed a method of neuronal operant conditioning, in which the emergence of a specific form of neuronal activities in hippocampal CA1 neurons of awake mice recorded via in vivo patch-clamp recordings were rewarded in the absence of associative behaviors through electrical stimulation on lateral hypothalamus, a reward-associated brain region. Here we report that mice can rapidly and selectively be trained to enhance barraged excitatory synaptic activities (bESAs) associated with ripple oscillations in a given hippocampal CA1 neuron, whereas no obvious enhancement of barraged inhibitory synaptic activities or bESAs in layer 2/3 neurons in the primary somatosensory cortex was observed. Placing contingency of reward on the bESA that satisfied the preset criteria resulted in the selective enhancement of bESAs without changing background synaptic activities, whereas bESAs did not increase during pseudo-conditioning with yoked control where rewards were not contingent. Pharmacological analysis revealed that the enhancement of bESAs required the activation of NMDA receptors. Paired recordings of hippocampal neurons demonstrated that the reinforcement occurred only in the conditioned neurons, not in the other unconditioned neurons even in the same hippocampus. Thus, mice are capable of routing ongoing action potential series into a specific neuronal pathway in the hippocampus. This neuronal operant conditioning signifies the volitional ability to self-control the brain activity and is thus useful for neural prosthetics, brain machine interface, and clinical treatment with psychological disorders, such as depression, posttraumatic stress disorder, and substance abuse disorder.	P3-2-8 神経可塑性に必要なドパミン放出はどのように決定されるのか Coincident stimulation of two independent pathways triggers dopamine release which enhances synaptic transmission in Drosophila mushroom bodies ○上野耕平1, 堀内純二郎1, 齊藤実1 ○Kohei Ueno1, Junjiro Horiuchi1, Minoru Saitoe1 東京都医学総合研究所・学習記憶プロジェクト1 Mol. Physiol. Memory, Dept. Motor and Sensory Sys., Tokyo Met. Inst. Med. Sci., Tokyo, Japan1 Simultaneous stimulation of the antennal lobe (AL) and the ascending fibers of the ventral nerve cord (AFV) produces long-term enhancement (LTE) of synaptic transmission between the AL and mushroom body (MB) neurons in isolated brains. LTE is proposed to be a cellular correlate of aversive olfactory memory in which Drosophila form associations between odors and electrical shocks, and both LTE and aversive olfactory memory require activity of acetylcholine receptors (nAChRs), NMDA receptors (NRs) and dopamine (DA) type1 receptors (D1Rs). DA signaling has previously been proposed to transmit shock information from the AFV to the MBs, since artificial activation of DA neurons can substitute for aversive electrical shocks in behavioral studies. However, we found that nAChRs are required for transmission of AL inputs to MBs, NRs are required for transmission of AFV inputs, and D1Rs are not required for either input but are required for enhancement. To understand the regulation and function of DA signaling during LTE formation, we examined whether AFV stimulation alone can induce DA release using synaptopHluorin imaging, and determined that AFV stimulation fails to release synaptic vesicles from DA neurons. We also observed that simultaneous electrical stimulation of the AL and activation of NRs by NMDA application induces LTE and this LTE is suppressed in D1R mutants. This suggests that D1Rs function downstream of simultaneous AL and NR stimulation. We next stimulated DRs by bath application of DA or activated DA neurons by photostimulation using channelrhodopsin-2, and found that activation of DRs alone in the absence of AL stimulation or NR activation is sufficient to induce LTE. Moreover, we found that simultaneous AL stimulation and NR activation induces DA release from DA neurons. Thus, coincident activation of MB nAChRs and NRs activates DA neurons and DA released from these neurons is sufficient to induce LTE in AL-MB synapses.
P3-2-9 自由行動下マウスにおけるニューロプシンによるシナプス可塑性制御の解析 Neuropsin regulates synaptic plasticity, in vivo analysis using freely moving mice ○秋葉惇1, 石川保幸1, 塩坂貞夫1 ○Atsushi Akiba1, Yasuyuki Ishikawa1, Sadao Shiosaka1 奈良先端大・神経機能科学1 Laboratory of Functional Neuroscience, Nara Institute of Science and Technology, Nara, Japan1 Cognition and memory are involved in endogenous modification of synaptic plasticity. Synaptic plasticity is supposed to be a cellular mechanism that is involved in memory formation. It can be separated into a protein synthesis-independent form (early phase -) and a protein synthesis-dependent form (late phase - long term potentiation(LTP)). Furthermore neural oscillations are associated with synaptic plasticity. In our previous study, we found that synaptic plasticity in the hippocampal Schaffer collateral pathway depended on neuropsin (KLK8), a plasticity-related extracellular protease in acute hippocampal slices and in anaesthetized mice. However, neuropsin dependent synaptic plasticity in freely moving mice remains poorly understood. Therefore, we investigated the neuropsin-dependent effect of early phase LTP and novelty-exploration with early phase LTP in the hippocampal CA1 of freely moving mice. We found that neuropsin-knockout mice were significantly impaired in early phase LTP induced by a single tetanus in vivo. Furthermore, we try to investigate that neuropsin-dependent endogenous modification of brain oscillations. We will discuss about the functions of neuropsin on our new findings.	P3-2-10 ホスホチロシンアダプターShcBによるプルキンエ細胞カルシウムストアの機能維持 Functional regulation of intracellular calcium store by phosphotyrosine adaptor ShcB in cerebellar Purkinje cells ○柿澤昌1,3, 岸本泰司2, 山本伸一郎1, 大神和子3, 安田邦彦3, 堺隆一4, 竹島浩1, 森望3 ○Sho Kakizawa1,3, Yasushi Kishimoto2, Shinichiro Yamamoto1, Kazuko Onga3, Kunihiko Yasuda3, Ryuichi Sakai4, Hiroshi Takeshima1, Nozomu Mori3 京都大院・薬・生体分子認識1, 徳島文理大・香川薬・生物物理2, 長崎大・医歯薬総合・神経形態3, 国立がんセンター研・転移浸潤シグナル4 Dept Biol Chem, Grad Sch Pharmaceu Sci, Kyoto Univ, Kyoto1, Dept Biophysics, Kagawa Sch Pharmaceu Sci, Tokushima Bunri Univ2, Dept Anat, Grad Sch Biomed Sci, Nagasaki Univ3, Div Metastasis Signal, Natl Cancer Res Inst4 Tyrosine phosphorylation system and calcium signaling are involved in various cellular events. However, the mechanisms underlying crosstalk between these two signaling pathways are largely unknown. We show here evidence that ShcB, a phosphotyrosine adaptor expressed in central neurons, is involved in functional regulation of intracellular Ca2+ store. Using ShcB gene-deficient (ShcB-KO) mice, we revealed that ShcB dysregulation affects cerebellar-dependent motor learning and synaptic plasticity, i.e., long-term depression, at the parallel fiber-Purkinje cell (PC) synapse. Most notably, intracellular Ca2+ store was almost depleted, and Ca2+ release was nearly abolished in ShcB-KO PCs. These results suggest indispensable roles of phosphotyrosine adaptor in regulating adult brain function and novel signaling platform in the endoplasmic reticulum Ca2+ store in central neurons.
P3-2-11 海馬CA1領域におけるシータバースト刺激による長期増強の時空間的可視化：膜電位感受性色素を用いた光計測法による解析 Spatio-temporal visualization of the theta-burst induced long-term potentiation at hippocampal CA1 area: analysis using an optical imaging method with voltage-sensitive dye ○近藤将史1, 海江田岳3, 相原威1,2,3 ○Masashi Kondo1, Gaku Kaieda3, Takeshi Aihara1,2,3 玉川大院・脳情報1, 玉川大・脳研2, 玉川大・工3 Grad. Sch. of Brain Sciences, Tamagawa Univ., Tokyo1, Brain Science Inst., Tamagawa Univ., Tokyo2, College of Engineering, Tmagawa Univ., Tokyo3 Hippocampal CA1 networks have complex excitatory and inhibitory circuits, which play a crucial role in information processing. For these circuits, previous studies showed that theta (4 - 8 Hz)-related inputs from the other areas might be important. Some investigators reported that synaptic plasticity formed at hippocampal CA1 area was not uniform along the somato-dendritic axis. In other words, the synaptic plasticity is mapped differently depending on structures of the local circuits in CA1 area. However, to reveal this phenomenon, a spatio-temporal recoding method was needed. Hence, in this study, employing an optical imaging method with voltage-sensitive dye (VSD), we tried to measure long-term synaptic modifications induced by theta-burst stimulation at hippocampal CA1 networks. As a result, using data measured by VSD imaging, we could perform some analysis; for example, analysis of the time-course of membrane potentials among dendrites and the spatial distribution of potentiation ratio. These analyses cannot be performed by traditional recording methods for electrophysiology, especially patch-clamp recording. Therefore, these results suggest new viewpoints about spatio-temporal properties of long-term synaptic modifications in hippocampal CA1 area.	P3-2-12 CaMKIIβ as a gating mechanism of activity-induced structural modification of hippocampal dendritic spines ○Karam Kim1, Lakhanpal Gurpreet2, Khan Mustafa2, Akio Suzuki1, Mariko Kato-Hayashi3, Narayanan Radhakrishnan3, Tomoki Matsuda4, Takeharu Nagai4, Yasunori Hayashi1, Kenichi Okamoto2 RIKEN Brain Science Institute Room S508, Central Building1, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Canada2, The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan3 The size of the synapse is the major determinant of input strength. Therefore, how synaptic structure is modulated by activity is essential for the mechanism of synaptic plasticity. Here we demonstrate that Ca2+/calmodulin-dependent protein kinase (CaMKII), the pivotal kinase in synaptic plasticity, mediates activity-dependent structural modification of excitatory synapses through a novel activity-regulated F-actin stabilizing function, apart from well-known kinase signaling. This involves F-actin bundling ability of CaMKII which is negatively regulated by Ca2+/calmodulin activation and the resultant autophosphorylation reaction on multiple serines and threonines within the F-actin binding domain. This allows unbundling of F-actin, which opens a temporary time window of ~1 min where F-actin remodeling by actin modifiers such as cofilin, Arp2/3, and gelsolin can take place and impact structural plasticity of dendritic spines. These observations make CaMKII a unique F-actin regulating mechanism with a permissive role in structural regulation by synaptic activity, thereby acting as a gate of activity-dependent modification of synaptic structure.
P3-2-13 Withdrawn

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