一般口演
神経伝達物質とシグナル分子
Neurotransmitters and Signaling Molecules
座長：礒村 宜和（東京医科歯科大学大学院医歯学総合研究科） |
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| 2022年6月30日 9:00～9:15 沖縄コンベンションセンター 会議場B3・4 第6会場
1O06m1-01
L-DOPA は線条体間接路における GPR143 と ドパミン D2 受容体間相互作用を介して不安様行動を制御する
L-DOPA modulates anxiety-like behavior through coupling between GPR143 and dopamine D2 receptors in the indirect pathway striatal neuron
*増川 太輝(1)、五嶋 良郎(1)
1. 横浜市立大学
*Daiki Masukawa(1), Yoshio Goshima(1)
1. Yokohama city university
Keyword: L-DOPA, GPR143, dopamine D2 receptor, indirect pathway
We propose that L-DOPA is a neurotransmitter. We identified G-protein coupled receptor (GPCR) GPR143, a gene product of ocular albinism-1, as a receptor for L-DOPA. We found that the decrease in locomotor activity to a dopamine D2 receptor (D2R) agonist quinpirole was attenuated in Gpr143 gene-deficient (Gpr143-/y) mice when compared to wild type (WT) mice. The impairment of responsiveness to quinpirole was also observed in the striatal indirect pathway specific Gpr143 gene-deficient (A2A-cre;Gpr143flox/y) mice. To investigate the role of GPR143, we assessed anxiety-like behavior using zero maze test, in which the time spent in open arms is altered in the striatal indirect pathway specific D2R deficient mice. The time spent in open arms was decreased in both Gpr143-/y and A2A-cre;Gpr143flox/y mice when compared to corresponding control mice. To clarify whether endogenous L-DOPA was involved in the anxiety-like behavior, we employed a-methyl para tyrosine methyl ester (aMPT), a tyrosine hydroxylase inhibitor at a dose that selectively reduced the release of L-DOPA, but not that of dopamine monitored by in vivo microdialysis of the dorsomedial striatum. The aMPT treatment decreased the time spent in open arms when compared to saline-treated WT mice, while it did not affect the time spent in open arms in Gpr143-/y mice. These results suggest that the L-DOPA receptor GPR143 fine-tunes the D2R-mediated dopaminergic transmission in the striatal indirect pathway. | | 2022年6月30日 9:15～9:30 沖縄コンベンションセンター 会議場B3・4 第6会場
1O06m1-02
行動中マウスの大脳皮質体性感覚野第II/III層神経細胞におけるPKA 活性イメージング
PKA activity in layer II/III of somatosensory cortex in behaving mice
*野村 しのぶ(1)、Philipp Flotho(2)、Bernd Kuhn(1)
1. 沖縄科学技術大学院大学
*Shinobu Nomura(1), Philipp Flotho(2), Bernd Kuhn(1)
1. Optical Neuroimaging Unit, Okinawa Institute of Science and Technology, Okinawa, Japan, 2. Systems Neuroscience and Neurotechnology Unit, Neurocenter, Faculty of Medicine, Saarland University & School of Engineering
Keyword: catecholamine, in vivo imaging, PKA, GPCR
The catecholaminergic system influences animal behavior by controlling the excitability of neurons through G-protein coupled receptors and second messengers including cAMP/PKA signaling. However, little is known about the real-time cellular dynamics of endogenous catecholaminergic transmission in awake animals. Here, we imaged protein kinase A (PKA) activity in dendrites and somata of cortical layer 2/3 of awake mice with two photon microscopy and the single-chromophore PKA sensor GakdYmut with high temporal resolution (6.2Hz). For simultaneous PKA and Ca2+ imaging, we combined GakdYmut and the red Ca2+ sensor jR-GECO1a. Furthermore, we applied antagonists of Gs-coupled receptor and Gi-couped receptor to investigate pharmacological modification of PKA activity. When switching from isoflurane anesthesia (1%) to full wakefulness, the basal PKA activity increased by 22% and 12% in dendrites and somata, respectively (440 dendrites, 190 somata, 5 mice). During anesthesia and wakefulness, the PKA activity was suppressed by the β adrenoceptor agonist propranolol and D1 receptor antagonist sch23390. In contrast, α2 adrenoceptor antagonist yohimbine increased PKA activity. During wakefulness, we detected Ca2+ activity increase that synchronized with the locomotion of mice. However voluntary running induced typically biphasic PKA activity: decrease during locomotion followed by an overshooting rebound peaking about 25s after locomotion offset. Individual somata and dendrites showed a continuum of responses from only decrease during running to only increase after locomotion and changed their response type with every locomotion event. PKA activity was not correlated with Ca activity in dendrites and somata. Yohimbine increased locomotion induced PKA activity. Since yohimbine potentiates PKA activity by suppressing pre- and post-synaptic α2 receptor, this experiment indicated the involvement of NA and adrenoceptors for voluntary locomotion PKA change. Forced running, being a stress stimulus, induced a more homogeneous PKA response in dendrites and somata. | | 2022年6月30日 9:30～9:45 沖縄コンベンションセンター 会議場B3・4 第6会場
1O06m1-03
アセチルコリンのリン酸化プロテオミクス解析による忌避シグナルとして作用するPKC-β-PIX-Rac1-PAKシグナルの活性化経路の同定
Phosphoproteomics of the acetylcholine pathway enables discovery of the PKC-β-PIX-Rac1-PAK cascade as a stimulatory signal for aversive learning
*山橋 幸恵(1)、林 裕新(2)、岩永 渉(3)、川島 知浩(3)、徳元 友哉(3)、渡部 洋(3)、Faruk Md. Omar(3)、張 心健(1)、坪井 大輔(1)、斎藤 尚亮(4)、永井 拓(1)、山田 清文(3)、貝淵 弘三(1)
1. 藤田医科大学、2. テキサス大学サウスウェスタンメディカルセンター、3. 名古屋大学、4. 神戸大学
*Yukie Yamahashi(1), You-Hsin Lin(2), Sho Iwanaga(3), Kazuhiro Kawashima(3), Yuya Tokumoto(3), Yo Watanabe(3), Md. Omar Faruk(3), Xinjian Zhang(1), Daisuke Tsuboi(1), Naoaki Saito(4), Taku Nagai(1), Kiyofumi Yamada(3), Kozo Kaibuchi(1)
1. Fujita Health University, 2. University of Texas Southwestern Medical Center, 3. Nagoya University, 4. Kobe University
Keyword: Acetylcholine, phosphoproteomics, Rac/PAK signal, aversive learning
Acetylcholine is a critical neuromodulator for learning and memory. The cholinesterase inhibitor donepezil increases acetylcholine levels in the brain and improves learning disabilities in Alzheimer’s disease patients. Acetylcholine activates dopamine receptor D2-expressing medium spiny neurons (D2R-MSNs), which regulate aversive learning, in the striatum/nucleus accumbens through muscarinic receptor M1 (M1R). However, how acetylcholine stimulates learning ability beyond the M1R remains unresolved. Here, we found that acetylcholine stimulated protein kinase C (PKC) in striatum/nucleus accumbens slices from mice. Our originally developed kinase-oriented phosphoproteomic analysis of the slices revealed 116 PKC substrate candidates, including the Rac1 activator β-PIX. Acetylcholine induced the phosphorylation and activation of β-PIX, thereby stimulating p21-activated kinase (PAK), the effector of Rac1. Aversive stimulus activated the M1R-PKC-PAK pathway in D2R-MSNs in mice. D2R-MSN-specific expression of PAK mutants by the Cre-Flex system regulated dendritic spine structural plasticity and aversive learning. Donepezil induced PAK activation not only in accumbal D2R-MSNs but also in the CA1 region of the hippocampus and enhanced D2R-MSN-mediated aversive learning. These findings demonstrate that acetylcholine stimulates the M1R-PKC-β-PIX-Rac1-PAK cascade in D2R-MSNs for aversive learning, providing a new direction for the therapeutic strategy of modifying Rac1-PAK activation for CNS disorders with learning disabilities. | | 2022年6月30日 9:45～10:00 沖縄コンベンションセンター 会議場B3・4 第6会場
1O06m1-04
FMRFamide様神経ペプチドFLP-2は餌のシグナルを仲介してC.エレガンスの塩走性を調節する
FMRFamide-like neuropeptide FLP-2 may modulate salt chemotaxis of C. elegans by mediating food signals
*謝 宇騁(1)、國友 博文(1)、山田 康嗣(1)、安達 健(1)、飯野 雄一(1)
1. 東京大学大学院理学系研究科
*Yucheng Xie(1), Hirofumi Kunitomo(1), Koji Yamada(1), Takeshi Adachi(1), Yuichi Iino(1)
1. The University of Tokyo, Graduate School of Science
Keyword: Neuropeptides, Chemotaxis, Caenorhabditis elegans
Neuropeptides modulate a variety of biological processes such as foraging, reproduction, learning and memory by regulating synaptic transmission between neurons. In this research, we screened neuropeptides that potentially act in salt chemotaxis learning of Caenorhabditis elegans, a type of associative learning in which experience of salt concentration and nutrition impacts the behavior. Wild-type worms migrate towards the salt concentration at which they have been fed, whereas avoid it if they have been starved. We found that 20 out of 36 neuropeptide-over-expression strains to some extent showed defects in salt chemotaxis. Especially, over-expression of an FMRFamide-like neuropeptide FLP-2 caused a reversed salt concentration preference under starvation conditions. FLP-2 was known to promote arousal by (mutually) activating secretion of PDF-1 (Chen D. D., et al. 2016), which is another neuropeptide that represents food abundance (Luo J., et al. 2021). We found that over-expression of PDF-1 shows a phenotype similar to that of FLP-2, but the effect of FLP-2 over-expression does not depend on pdf-1. Mutations in flp-2, pdf-1, their characterized receptors, or their regulator npr-1 does not result in salt chemotaxis defects, suggesting that other molecules may be involved in this process. In addition, FLP-2 antagonistically functions with INS-1 insulin in AIA interneuron to promote reproductive growth (Chai C. M., et al. 2021). AIA-specific expression of flp-2 reproduced the chemotaxis defects, implying that FLP-2 may mediate food signals or blocks starvation signals in salt chemotaxis learning via AIA. | |
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