嗅覚、味覚、化学感覚 Olfaction, Taste, Chemical Senses
P1-1-138 ムスク系香料の嗅覚系における認識メカニズムの解明 Narrow tuning of specific dorsomedial glomeruli for detection of macrocyclic musk odors in the mouse olfactory bulb ○白須未香1, 東原和成1 ○Mika Shirasu1, Kazushige Touhara1 東京大学　大学院農学生命科学研究科　応用生命化学専攻 生物化学研究室1 Department of Applied Biological Chemistry, The University of Tokyo, Tokyo1 Musk odorants are widely utilized in cosmetic industries because of their fascinating animalic scent. However, how this aroma is perceived in the mammalian olfactory system remains a great mystery. Here we developed a novel technique for imaging a previously inaccessible olfactory bulb (OB) that will allow for completion of the odor map and identified the olfactory neural pathway in mice that is activated by musk signals. Muscone, one of the most popular musk odorants, activates a few glomeruli clustered in the neuroanatomically unique antero-dorsomedial OB. Anterodorsal bulbar lesions cause muscone anosmia, suggesting that this region is crucial for muscone perception. The muscone-responsive glomeruli are highly specific to macrocyclic ketones musks (muscone, cyclopentadecanone, and ambretone), while other musk odorants having nitro or polycyclic moieties activate distinct, but nearby glomeruli. Together with c-Fos assays in the forebrain areas, the current study suggests that muscone is recognized by a few narrowly tuned olfactory receptor(s) and that the spatially converged signal in the OB is, in turn, widely distributed in the olfactory cortex.	P1-1-139 魚類における性行動発現の嗅覚メカニズム：性フェロモン・プロスタグランジンF2αが活性化するゼブラフィッシュ嗅覚受容体および神経回路素子の同定 Identification of the receptor and neural circuitry activated by the sex pheromone prostaglandin F2α in zebrafish ○矢吹陽一1,2, 小出哲也1, 宮坂信彦1, 脇阪紀子1, 増田美和1, 告恭史郎3, 土屋創健3, 杉本幸彦3, 渡邉和忠2,4, 吉原良浩1 ○Yoichi Yabuki1,2, Tetsuya Koide1, Nobuhiko Miyasaka1, Noriko Wakisaka1, Miwa Masuda1, Kyoshiro Tsuge3, Soken Tsuchiya3, Yukihiko Sugimoto3, Kazutada Watanabe2,4, Yoshihiro Yoshihara1 理研・BSI・シナプス分子機構1, 長岡技大・生物2, 熊本大・薬3, 長岡高専4 Lab. for Neurobiology of Synapse, RIKEN BSI, Wako, Japan1, Dept. Bioeng., Nagaoka Univ. Tech., Nagaoka, Japan2, Grad. Sch. Pharm. Sci., Kumamoto Univ., Kumamoto, Japan3, Nagaoka Natl. Coll. Tech., Nagaoka, Japan4 Pheromones are conspecific olfactory cues which elicit various innate responses in many animal species including fishes. In teleost fishes, prostaglandin F2α (PGF2α) has been proposed as a putative sex pheromone. In goldfish, for example, PGF2α is released from ovulated females and evokes typical reproductive behaviors of males (e.g., increase of swimming activity and nudging). However, the receptor and olfactory neural circuitry mediating PGF2α-evoked reproductive behaviors are largely unknown. Here, we used zebrafish to address these issues because of its genetic amenability for visualization and manipulation of selective neural circuits. Upon PGF2α application, male zebrafish showed attractive response. Immunohistochemistry with phosphorylated Erk, a marker for odor-evoked neuronal activation, revealed that PGF2α activates a small population of ciliated olfactory sensory neurons in the olfactory epithelium, a few specific ventromedial glomeruli in the olfactory bulb, and several nuclei in the ventral forebrain. Furthermore, we identified one candidate receptor for pheromonal PGF2α by double in situ hybridization with probes for c-fos and olfactory receptor genes. In vitro expression analysis in COS7 cells validated that this candidate receptor is specifically activated by PGF2α to produce intracellular cAMP. Interestingly, ligand specificity and G-protein selectivity of this pheromonal PGF2α receptor were different from those of hormonal PGF2α receptor. These results provide molecular, anatomical, and functional bases of the olfactory neural circuitry mediating PGF2α-induced sexual behavior in zebrafish.
P1-1-140 ラットの甘味感受性に対するオキサリプラチンの影響 Effect of oxaliplatin on the sensitivity for sweeteners in the rats ○西田健太朗1, 山中優里1, 宮田麻依1, 小西一誠1, 藪美晴1, 塚本勝信1, 大石晃弘1, 長澤一樹1 ○Kentaro Nishida1, Yuri Yamanaka1, Ai Miyata1, Issei Konishi1, Miharu Yabu1, Katsunobu Tsukamoto1, Akihiro Ohishi1, Kazuki Nagasawa1 京都薬科大学　衛生化学1 Dept. of Environ. Biochem., Kyoto Pharm. Univ., Kyoto1 As one of the adverse effects of chemotherapy, taste disorder decreases the quality of life of the patients. In general zinc deficiency induced by the ion-chelating activity of drugs is believed to be an underlying mechanism. However, drug-related taste disorder is about half of the patients is known to be not improved by zinc administration. Oxaliplatin, a platinum anticancer drug, has a critical role in colon cancer chemotherapy, and it reported to induce taste disorder at high frequency, but there is no report on its underlying molecular mechanism. In this study, therefore, we investigated expression of taste receptors in the circumvallate papillae of the oxaliplatin-administered rats by real-time PCR and immunohistochemistry. Among of taste receptors, the mRNAs for T1r2 increased in the circumvallate papillae of the oxaliplatin-treated rats at day 7, while T1r1, 3, T2r4 and mGlur4 mRNA levels were not. The T1r2-immunoreactivity was increased dose-dependently in the circumvallate papillae of the oxaliplatin-treated rats. These results pointed out the possibility that sensitivity for sweeteners is affected by oxaliplatin, and upregulation of mRNAs for T1r2 might be involved in the oxaliplatin-induced taste disorder.	P1-1-141 ラット延髄孤束核味覚応答へのオキシトシンの影響 Influences of oxytocin to the taste responses in the rostral nucleus of the solitary tract in the rat ○横田たつ子1, 平場勝成1 ○Tatsuko Yokota1, Katsunari Hiraba1 愛知学院大学　歯学部　生理学講座1 Dept Physiol, Aichi-Gakuin Univ, Nagoya1 Proper intake of sodium salts is highly important in maintaining the normal sodium level of body fluid. Previous electrophysiological studies have reported that the taste responses to NaCl in the rostral nucleus of the solitary tract (rNST), the first-order taste relay, were reduced in the rats whose salt appetites were evoked through a sodium-deprived diet. It is likely that sodium-deprived rats perceived NaCl solution as being lower (acceptable) in concentrations than they actually were, so that they could fully intake the sodium into their body fluid. The information for the sodium levels in the brain appears to be conveyed by the descending fibers containing the neuropeptide oxytocin from the paraventricular nucleus (PVN) of the hypothalamus to the rNST. Numerous behavioral studies have demonstrated that the intracerebroventricular administration of oxytocin inhibited the salt appetite. Here, we examined the influence of oxytocin on the taste responses in the rNST. Multi-barrel glass micropipettes were used to record extracellular single unit activities, for the iontophoretic application of the oxytocin and the vesicle under urethane anesthesia. Oxytocin applied to taste-sensitive neurons in the rNST primarily affected the taste responses to NaCl, although the spontaneous activities were unchanged. The influences were restricted in the tonic responses (5sec subsequent to the initial 1sec from the stimulus onset) but not in the phasic responses (the initial 1sec). These results may indicate that oxytocin modulates the activity levels in the taste-sensitive neurons in the rNST.
P1-1-142 味覚に関わるアメフラシ中枢神経ネットワークの蛍光膜電位イメージングによる解析 Possible neural network involved in taste recognition in Aplysia buccal ganglion by voltage sensitive dye imaging ○三宅祐輝1 ○Yuki Miyake1 芝浦工業大学　工学部　応用化学科　化学工学研究室1 Dept Applied Chemistry, Shibaura Institute of Technology, Tokyo1 Taste is sensed by chemoreceptors and identified by a sophisticated neural network. Analysis of the neural network concerning about taste will contribute to understand informational processing in the central nervous system.A marine gastropod Aplysia has large neurons and shows clear food preferences. We attempted to analyze the neural network which generates ingestive or rejective response by using fluorescent voltage dye imaging. A buccal mass and a buccal ganglion were enucleated with keeping their connection by buccal nerves. The S cluster sensory neurons in the ganglion were stained with voltage sensitive dye (Di-4-ANEPPS) in the presence of tetraethylammonium (TEA) chloride. Then the responses of the stained neurons were explored after administration of 1 mM solution of L-asparagine or L-aspartic acid which induces ingestive or rejective response of the jaws and radula respectively to the inner surface of the buccal mass. Administration of asparagine or aspartic acid induced 1-5 spikes in S2 cluster neurons. On the other hand, administration of asparagine induced 1-5 spikes but that of aspartic acid induced more than 30 spikes in S1 cluster neurons. These results suggest that the neural network for taste recognition may exist in the S1 cluster in Aplysia buccal ganglion. Further approach by using the voltage imaging would disclose neural network underlying recognition of taste.	P1-1-143 香りは女性の魅力を増す The Scents Increase Female Allure ○豊島久美子1, 福井一1, 駒木亮一2 ○Kumiko Toyoshima1, Hajime Fukui1, Ryoichi Komaki2 奈良教育大学教育学部1, 株式会社カネボウ化粧品 技術部門 スキンケア研究所2 Dept Edu, Nara Univ of Edu, Nara1, Kanebo Ltd. Cosmetics laboratory, Japan2 ObjectThe physical beauty is often represented by averageness (well-balanced symmetricity), one of the primary factors for attracting others. At the same time, it represents health and fertility in its DNAs. It has been discovered that male finds female face digitally equalized to be symmetrical attractive. Communication through scents plays a central role in the mammals' mating behaviour. In human behaviour too, the report states that male evaluate female attraction by her scents (body odour). Would the scents that had been added to female artificially influence males' appraise on her? In this report, 2 types of female photographs, digitally equalized to be symmetrical thus enhanced allure and digitally mixed without making it to be symmetrical, were shown with an artificial scent to males to inspect their evaluation on female attraction. MethodSubjects: 40 males with healthy olfaction. Procedure: Photographs of digitally equalized to be symmetrical female face and digitally created female face without editing were shown on screen for a short time, then male subjects were asked to smell odour stimuli. Stimuli (Photographs): Several Japanese female facial images with digitally equalized to be symmetrical and digitally created but unsymmetrical. Stimuli (Odours): 1.Rose, 2.Musk, 3.FragranceL, 4.FragranceR, 5.Tobacco, 6. Odourless (Controlled) ResultsThe valuations of images were significantly differed by odour stimuli. There was no valuation difference between the symmetrical and unsymmetrical faces. The evaluation became the highest when the subjects smelled SL36 or RR35. Rose, Musk and Odourless follow and the valuation was the lowest with Tobacco odour. It is common for female to dress up with perfumes and one of the main purposes is to attract other sex. This research has proved that artificially added odours affect males' appraisal on female and varied types of odour can even differentiate the valuation.
P1-1-144 カイコガ触角葉の神経活動からの匂い情報のデコーディング Decoding odor identity from neural activity in the moth antennal lobe ○小林亮太1, 並木重宏2, 神崎亮平2, 北野勝則1, 西川郁子1 ○Ryota Kobayashi1, Shigehiro Namiki2, Ryohei Kanzaki2, Katsunori Kitano1, Ikuko Nishikawa1, Petr Lansky3 立命館大学 情報理工学部1, 東京大学 先端科学技術センター2, チェコ科学アカデミー3 Dept Human and Computer Intelligence, Ritsumeikan University, Japan1, Research Center for Advanced Science and Technology, The University of Tokyo2, Institute of Physiology, Academy of Sciences of Czech Republic3 We investigated how odorant information is transmitted by neurons in the moth antennal lobe. The neurons were repeatedly stimulated by three different odorants and their activity was recorded. We attempted to decode the odorant identity from the neural activity. The decoding performance improves with the increase of the number of neurons. The increase in the number of neurons results in rapid information transfer and high information retaining capacity. In conclusion, the population coding is important for the neurons in the antennal lobe to transmit the olfactory information fast and reliably.	P1-1-145 加齢に伴う味覚嗜好性の変化 The changes in taste preference by aging in rats ○乾千珠子1, 山本隆2, 上田甲寅1, 中塚美智子1, 安春英1, 隈部俊二1, 岩井康智1 ○Chizuko Inui-Yamamoto1, Takashi Yamamoto2, Katsura Ueda1, Michiko Nakatsuka1, Chunyon An1, Shunji Kumabe1, Yasutomo Iwai1 大阪歯科大・口腔解剖1, 畿央大・健康科学2 Dept Oral Anatomy, Osaka Dental Univ, Hirakata1, Fac Human Health Sci, Kio Univ, Nara2 Tastes play important roles in detecting nutrients and irritant materials in food. Preference for food tastes is critical for ingestive behavior because greater palatability is to evoke greater food intake. Taste preferences are known to be affected by aging which causes changes in the dietary and energy requirements. However, the mechanisms of shift in taste preference by aging still remain unclear. Therefore, to elucidate differences in taste preference among the life stages, firstly, we investigated preferences to several taste solutions in different ages of rats. Secondly, we recorded responses of the chorda tympani nerve to taste stimuli. We used juvenile (3-6 weeks), young-adult (8-11 weeks), adult (17-20 weeks), middle-aged (34-37 weeks) and old-aged (69-72 weeks) Sprague-Dawley male rats. All rats were fed ad libitum during all tests. We compared intakes between 0.1 M and 0.3 M NaCl, 10 mM and 50 mM HCl, 0.3 M and 0.5 M sucrose (Suc), 5 mM and 50 mM saccharin-Na (Sac), 0.3 mM and 0.03 mM quinine-HCl (QHCl), and 0.1 M and 0.3 M monosodium glutamate (MSG). The preference ratio for 0.3 M NaCl and 0.3 M MSG in old-aged was higher than that in other groups. The preference ratio for 0.5 M sucrose in old aged was higher than that in juvenile and middle-aged group. The preference ratio for 0.3 mM QHCl in old-aged was higher than that in juvenile and young-adult groups. There was no significant difference in the preference for HCl and Sac tastes among groups. The responses of the chorda tympani nerve to taste stimuli were not different among groups. These results suggest that aging changes taste preferences, but aging does not affect the neural activity of the chorda tympani nerve.
P1-1-146 単一の感覚ニューロンによって制御される飼育温度に依存した低温耐性 Single sensory neuron controls cultivation temperature-dependent cold tolerance in C. elegans ○宇治澤知代1, 桑原直人2, 太田茜2, 久原篤2 ○Tomoyo Ujisawa1, Naoto Kuwahara2, Akane Ohta2, Atsushi Kuhara2 甲南大学大学院 自然科学研究科 生物学専攻1, 甲南大学 理工学部 生物学科2 Dept. of Bio., Grad. Sch. of Nat. Sci., Konan Univ.1, Dept. of Bio., Facul. of Sci. & Eng., Konan Univ.2 Animals have adaptation mechanisms against environmental temperature changes. To understand its molecular mechanism, we are using simple model animal, nematode C. elegans. We recently found that C. elegans shows cultivation temperature-dependent cold tolerance, which is regulated by a single sensory neuron. After cultivation at 25 degree, C. elegans were destroyed by 2 degree cold stimuli. By contrast, most of animals can survive at 2 degree, after cultivation at 15 degree. Importantly, when 25 degree-cultivated animals are transferred to 15 degree and cultivated at 15 degree for only 3 hrs, animals can survive at 2 degree. This indicates that temperature memory for cold tolerance can be replaced for only 3 hrs. In order to determine the cells and genes underlying cultivation temperature-dependent cold tolerance, we utilized various mutants. We found that the mutant animals defective in TAX-4 cGMP-gated channel, which is expressed in 10 pairs of sensoryneurons, showed abnormal enhancement of cultivation temperature-dependent cold tolerance. The abnormality in tax-4 mutant is rescued by the specific expression of tax-4 cDNA in a single sensory neuron ASJ, which has been known as a photosensory and chemosensory neuron. Developmental defect in AFD known as thermosensory neuron did not affect the cold-resistance. These results suggest that cultivation temperature-dependent cold tolerance is controlled by ASJ sensoryneuron, and that ASJ negatively regulate the cold tolerance. Since the expression level of a trimetric G protein-coupled receptor TRX-1 in ASJ is altered by temperature stimuli, it is possible that the ASJ act as a thermosensory neuron. We are utilizing calcium imaging to examine the possibility. To determine a molecular pathway for cultivation temperature-dependent cold tolerance, we referred previous DNA microarray analysis (Sugi et al., Nature neurosci., 2011). So far, 8 genes such as endonuclease and cysteine protease are involved in the cold tolerance.	P1-1-147 期待によって生じる味認識の神経機能 Neural mechanism of taste perception elicited by expectation ○松岡俊輔1, 樫森与志喜1,2 ○Shunsuke Matsuoka1, Yoshiki Kashimori1,2 電気通信大学院　情報システム学研究科　情報メディアシステム学専攻1, 電気通信大学　情報理工学研究科2 Graduate School of Information Systems, University of Electro-Communications, Chofu, Tokyo, Japan1, Dept. of Engeneering Science, University of Electro-Communication, Chofu, Tokyo, Japan2 Tate, besides smell, contributes to our experience of environment, from the pleasure of eating to the formation of childhood memories. How are the information about taste qualities (e. g. salty, sour, sweet, and bitter) and intensity represented by activity in the nervous system? This question lies at the center of a long-standing debate in the field of gustatory neurobiology. In that time, two major theories have emerged that have dominated the literatures. There are the labeled-line theory and the across-neuron-pattern theory. However, it is not yet clear how the nervous systems process the information about taste quality and intensity. On the other hand, we seldom recognize experience of pure taste. Taste recognition is strongly influenced by other senses such as vision and smell. Additionally, it is also significaltly dependent on expectation and anticipation. However little is known about how expectation influences taste perception. We are concerned here with the neural mechanism of taste perception elicted by expectation. The basolateral amygdala (BLA) in rat has been reported to play an important role in taste expectation[1]. We developed a neural model of the gustatory system of rat including the primary gustatory cortex (GC) and the BLA. Using this model, we show that the GC integrates the information of taste components encoded by the hindbrain and represents the information of a mixed taste as a temporal sequence of dynamical attractors. We also show that a top-down signal from the BLA brings the membrane potentials of GC neurons to just below the firing threshold, leading to a rapid perception of taste. The present study provides a new insight into understanding how expectation improves the pocessing ability of gastatory information in GC. [1] Samulelsen et al. Neuron 74: 410-422 (2012)
P1-1-148 レプチンは味細胞の甘味応答を抑制する Leptin affects sweet taste responses of mouse fungiform taste cells ○吉田竜介1, 高井信吾1, 仁木麻由1二ノ宮裕三1 ○Ryusuke Yoshida1, Shingo Takai1, Mayu Niki1, Robert F. Margolskee2, Yuzo Ninomiya1 九州大学大学院　歯学研究院　口腔機能解析学分野1, モネル化学感覚センター2 Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan1, Monell Chemical Senses Center, Philadelphia, USA2 Leptin, an anorexigenic mediator that reduces food intake by acting on hypothalamic receptors, selectively suppresses sweet taste responses. This effect would be mediated by leptin receptor Ob-Rb on sweet taste receptor cells. However, suppressive effect of leptin on taste responses of sweet sensitive taste cells still has not been elucidated. In this study, we examined the effect of leptin on sweet taste responses of taste cells in mouse fungiform taste buds. In about half of sweet sensitive taste cells, bath application of 20 ng/ml leptin suppressed responses to sweeteners (<80% of control response). The effect of leptin was concentration dependent and reached maximal level at 10-20 ng/ml. On the other hand, responses of sour sensitive taste cells to acids were not affected by bath application of leptin. When the cells were adapted to several concentrations (1-5 ng/ml) of leptin, increases in 10 ng/ml leptin still suppressed sweet responses of taste cells. These results indicate that leptin actually suppresses taste responses of sweet sensitive taste cells.	P1-1-149 ゼブラフィッシュ嗅球における匂い地図の包括的解析 Functional odor map in the zebrafish olfactory bulb ○小出哲也1, 脇阪紀子1, 宮坂信彦1, 大倉正道2, 中井淳一2, 吉原良浩1 ○Tetsuya Koide1, Noriko Wakisaka1, Nobuhiko Miyasaka1, Masamichi Ohkura2, Junichi Nakai2, Yoshihiro Yoshihara1 理化学研究所・脳科学総合研究センター・シナプス分子機構研究チーム1, 埼玉大学・脳科学融合研究センター2 Laboratory for Neurobiology of Synapse, RIKEN Brain Science Institute1, Saitama University Brain Science Institute2 Animals including fish can detect a variety of odorants, which evoke fundamental olfactory behaviors important for their survival, such as searching for foods, finding mates, and escaping from danger. Odor information is initially represented in the olfactory bulb (OB) by patterns of neural activation on the array of glomeruli. Therefore, understanding the logic of odor representations in the OB is the key step to elucidate neural circuit mechanisms underlying the odor-evoked behaviors. The adult zebrafish OB contains approximately 140 glomeruli innervated by three distinct morphological types of olfactory sensory neurons (OSNs). However, a comprehensive map of odor space created by glomeruli has yet to be clarified. In this study, we found that phosphorylated Erk (pErk) can be used as a reliable marker in neurons activated by a wide range of odor stimuli. Whole-mount OB immunohistochemistry revealed that odorants induced pErk in dendrites and somata of OB neurons located in proximity to particular glomeruli, thereby visualizing the activated glomeruli. Furthermore, we used genetically encoded calcium indicator GCaMP-HS, an improved version of GCaMP, under the control of the Gal4/UAS system, and measured odorant-evoked neural activities in the OB. In transgenic lines with GCaMP expression in OSNs, we detected a significant increase of calcium signals in distinct glomerular clusters of the OB upon application of different chemical classes of odorants. Thus, the combination of whole-mount OB pErk-immunohistochemistry and GCaMP Ca2+ imaging study successfully revealed the activation of different glomeruli upon stimulation with defined odorants or putative pheromones, such as amino acids (feeding cue), bile acids (social cue), prostaglandin F2α (sex pheromone), and conspecific skin extract (alarm pheromone). These findings will pave a new avenue to our understanding of the functional odor map underlying different olfactory behaviors in zebrafish.

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