{"created":"2023-06-19T07:19:22.023109+00:00","id":5423,"links":{},"metadata":{"_buckets":{"deposit":"264a286b-692c-4c1c-bfc8-589c84ae27e8"},"_deposit":{"created_by":4,"id":"5423","owners":[4],"pid":{"revision_id":0,"type":"depid","value":"5423"},"status":"published"},"_oai":{"id":"oai:az.repo.nii.ac.jp:00005423","sets":["370:15:391"]},"author_link":["23121"],"item_10006_date_granted_11":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2021-03-15"}]},"item_10006_degree_grantor_9":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"麻布大学"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"32701","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_10006_degree_name_8":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士(獣医学)"}]},"item_10006_description_22":{"attribute_name":"Abstract","attribute_value_mlt":[{"subitem_description":"Dogs were the first animals to be domesticated. They have a long history of coexisting with humans. During that time, dogs have developed human-like communication skills, including the ability to empathize with humans. It is thought that empathy of pleasant emotions lies behind the symbiotic and bonding relationship between humans and dogs. Furthermore, if there were a bond similar to that between human parents and children, then it could be expected that separation would be a source of stress and reunions would be joyful. Interestingly, dogs are reported to be extremely happy to see their owners again, but there is only limited research on the behavioral physiology of this response. In this study, we focused on the contexts where dogs were reunited with their owners and investigated the behavioral physiological changes in the dog that occurs at that time. \nIn Chapter 2, we conducted the experiment where dogs are separated and reunited with their owners on a daily basis to check whether there are changes in the amount of tear secretion associated with the change in the dog’s behavior. Given that oxytocin levels increase in dogs in the contexts involving interactions between them and humans and that oxytocin increases tear secretion and activates the parasympathetic nervous system, we hypothesized that oxytocin is also involved in the production of emotional tears and measured the tear volume after administration of oxytocin eye drops. The results revealed that there was no increase in tear volume during reunions with strangers, but only during reunions with the dog’s owner. Furthermore, there was an increase in tear volume due to the administration of oxytocin eye drops. This finding suggests that dogs secrete oxytocin through contact with their owners when reunited with their owners. It is thought that this oxytocin acts on oxytocin receptor cells in the lacrimal glands, which increases tear volume, so we considered it necessary to measure the serum oxytocin levels.\nIn Chapter 3, we verified the efficacy of rabbit anti-oxytocin polyclonal antibodies newly created in this laboratory and the reliability of the measurements. The results showed high sensitivity and specificity against to oxytocin, and there were high degree of correlations in the dilution test and spike recovery test. We obtained equivalent measurement results compared with the standard measurement method, indicating the establishing a oxytocin ELISA methods using a newly generated oxytocin antibody. However, we did not obtain any correlation with oxytocin in blood, which has been problematic to date, compared with the conventional RIA technique. This may be due to unknown molecular characteristics of oxytocin, such as changes to the three-dimensional structure of oxytocin caused by the extraction method and after extraction because oxytocin in the blood adheres to binding proteins. Although efforts have been made so far, it was deemed difficult to ascertain the blood kinetics, so it was decided to measure changes in oxytocin secretion by dogs that were reunited with their owners (covered in the next chapter) using the conventional RIA technique. \nIn Chapter 4, we found that the amount of tear volume increased when dogs were reunited with their owners, as seen in Chapter 2. The volume was higher than when the dogs encountered a stranger. However, there was no increase in oxytocin in that experimental settings. The oxytocin reduces by half within 3 minutes after secretion, so we are awaiting future development of technology that would enable it to measure the levels of hormones like oxytocin in the blood within a short time. Further verification of the changes in oxytocin and tear volume is required, either through fluctuations of oxytocin levels in the central nervous system or detailed sampling of oxytocin in the blood.\nIn Chapter 5, we instilled artificial tears in dogs’ eyes, took photographs of the dogs’ faces, and examined the impression humans had when viewing the photographs of the dogs to investigate the social effect of dogs shedding tears, focusing on the effect on humans’ feelings. We conducted a Wilcoxson signed rank-sum test comparing two types of photographs, one taken before the instillation of artificial tears and the other taken after, both involving the same dog, to determine if human evaluation differed with the photographs. The results indicated that, of the experiments conducted with thirteen pairs of photographs, the impression was significantly positive due to the presence of tears in seven pairs and negative with only one pair, suggesting that the presence of tears improved the positive impression of dogs.\nDogs had increased tear volume when reunited with their owners after a period of separation. This suggests that dogs exhibit emotional tears and manifest those tears with positive emotion (when reunited with their owners). This is the first time the presence of emotional tears in animals has been demonstrated. Furthermore, dogs showed no increase in tear volume when reunited with a stranger, and there was a significant increase in tear volume only when they reunited with their owners after a period of separation. Thus, it was found that the increase in tear volume occurs when dogs experience dramatic emotional changes such as reuniting with their owners with whom they have a special relationship after a period of separation. Moreover, oxytocin is an important hormone for building special relationships, and as tear volume increased with the administration of oxytocin eye drops, this suggests that the tear volume might have increased due to the increase in oxytocin secretion in dogs when reunited with their owners after a period of separation. Unfortunately, in Chapter 4, we were unable to clarify the correlation between elevated serum oxytocin levels in dogs reunited with their owners after a period of separation and oxytocin and tear volume. This research needs to be conducted with a higher level of accuracy. It was also clarified that changes in eye appearance with the instillation of artificial tears had a positive impact on humans. Dogs shedding emotional tears need to be further investigated by studies such as ones that seek to confirm the presence of emotional tears in wolves, but this finding suggests that these tears may be a function dogs acquired through the process of coexisting with humans, as it worked to their advantage. Dogs have highly evolved communication skills with humans by using their eyes, so tears may also perform the function of triggering protective and caring behavior in the dog’s owners. It might be possible to further unravel the history of symbiosis between dogs and humans in the future by combining these findings with the development of behavioral genetic studies. It is also known that the original role of tears in rodents is like a pheromone, and tears also function like a pheromone in humans. Tears may also function as a pheromone in dogs, so it will be necessary to clarify the function of dog tears within the same species."}]},"item_10006_description_7":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"イヌは最も早く家畜化された動物であり、ヒトとの共生の歴史が長い。その歴史の中でイヌはヒトに対する共感性を含め、卓越したコミュニケーション能力を身に付けてきた。ヒトとイヌの共生や絆の背景には、快情動の共感性の存在があると考えられる。またヒトの親子間で見られるような絆があるとすれば、分離がストレスになり、再会が喜びであると想像される。逸話的にはイヌは飼い主との再会で非常に喜ぶとされているが、その行動生理学的な研究は限られている。今回、我々は飼い主とイヌの再会場面に着目し、その時のイヌの変化を、行動生理学的に調べた。\n　2章ではイヌの情動の変化に付随して涙の分泌量が変化するのかを確認するために、日常的な飼い主との分離再会場面を用いて実験を行った。またイヌとヒトとの交流場面でイヌのオキシトシンも上昇すること (Odendaal et al. 2003, Handlin et al. 2011, Nagasawa et al. 2015)、オキシトシンが、涙液を増やす副交感神経系を賦活化させること（Norman et al. 2010, Romero et al. 2014） から、情動の涙にもオキシトシンが関与していると仮説を立て、オキシトシン点眼後の涙液量を測定した。その結果、涙液の増加は他人との再会では認められず、飼い主との再会時のみ認められた。さらにオキシトシンの点眼によって涙液量の増加が認められた。　このことは、飼い主との再開場面において、イヌが飼い主とのふれあいを介してオキシトシンを分泌し、そのオキシトシンが涙腺のオキシトシン受容体細胞に作用することで涙液量を増加させたと考え、オキシトシンの測定が必要と考えた。\n　脳内のオキシトシンの活性は測定することが困難なことから、脳下垂体から分泌されたオキシトシンを末梢にて計測することで、脳内オキシトシンの活性を捉える手法が一般的である。末梢では血中オキシトシンに加え、尿中、唾液中のオキシトシンが測定されるが、まだ安定した測定系は少ないのが現状である。\n　3章では本研究室で新たに作成したウサギ抗オキシトシンモノクローナル抗体の有用性とその測定の信頼性を検証した。その結果、高い感度と特異性、さらに添加回収試験でも高い相関性が見いだされ、また旧測定法との比較でもほぼ同等の測定結果が出るなど、新たなオキシトシン抗体の作成とそれを用いたオキシトシンELISA法を確立できた。一方、これまで困難と言われてきた血中のオキシトシンに関しては、従来のRIA法と比較し、相関が得られなかった。このことは、おそらく血中のオキシトシンが結合タンパク質に付着しており、抽出方法や抽出後におけるオキシトシンの立体構造の変化など、未だ明らかにされていないオキシトシンの分子特性によるものと思われる。新たに確立したELISA法では、血中動態を知ることが困難と判断し、次章の飼い主との再会場面におけるイヌのオキシトシン分泌変化に関しては、従来のRIA法によって、測定することとした。\n　4章では2章と同様に、イヌは飼い主との再会場面において涙液量が増加することがわかった。それは見知らぬ人と比較しても高かった。しかしながらその場面におけるオキシトシンの増加は認められなかった。オキシトシンの半減期は約3分といわれていることから、今後は、オキシトシンなどの血中ホルモンを、短い時間軸で計測できる技術の開発が待たれる。またオキシトシンと涙液量の変化に関しては、今後中枢でのオキシトシン変動あるいは、血中の詳細なサンプリングによる、さらなる検証が必要と考えられた。\n　5章では、イヌが涙を呈することによる、社会的な効果、特にヒトへの作用を調べるため、イヌに人工涙液を点眼して顔写真を撮影し、イヌの写真を見たヒトがどのような印象を持つかを調査した。同一犬で人工涙液点眼前と点眼後の2種の写真間において、Wilcoxson singed rankテストを実施し、写真間でヒトの評価が異なるかを検定した。その結果、13枚の写真のペアで実験を行ったうち、7ペアで涙によって印象が有意にポジティブとなり、1ペアでのみネガティブとなり、涙の存在によるイヌのポジティブな印象が上昇することが示唆された。\n　考察：飼い主との分離後の再会時において、イヌの涙液量の増加が認められた。このことは、イヌが情動性の涙、それも飼い主との再会という快情動場面での涙を呈することが示された。動物における情動性の涙の存在を示した最初の成果となった。また涙液の増加は他人との再会時には認められず、飼い主との分離後の再会時にのみ涙液量の有意な増加が見られた。涙液の増加はイヌと特別な関係性のある飼い主との分離後の再会のようにイヌの情動が激しく変化する場面において認められることが分かった。さらに、オキシトシンは飼い主とイヌを含む特別な関係を築く上で、重要なホルモンであると考えられているが、オキシトシンの点眼によって涙液量の増加が認められたことで、飼い主との分離後の再会によるイヌのオキシトシン分泌が上昇したことで、涙液量が増加した可能性が示された。一方、第4章では飼い主との再会場面におけるイヌのオキシトシン上昇、オキシトシンと涙液量の関係性は明らかにできなかった。この研究は、さらに精度を高めて実施する必要性がある。また、人工涙液による目の変化がヒトにポジティブな印象を与えることが明らかとなった。イヌが情動性の涙を呈することは、オオカミでの情動性の涙の存在の確認など追加の検討が必要であるものの、ヒトとの共生において有利に働き、その過程で獲得された機能である可能性が示された。視線を用いたヒトとのコミュニケーション能力を高度に進化させてきたイヌの涙にも飼い主の保護行動や養育行動を引き起こすような機能があるのかもしれない。\n　今後、行動遺伝学的研究の発展と組み合わせることで、さらにイヌとヒトの共生の歴史が紐解かれるかもしれない。また本来の涙の社会的役割はげっ歯類ではフェロモンであり、ヒトでもフェロモンとして機能していることが分かっている。イヌもフェロモンとしての機能を持っている可能性があり、今後イヌの涙がもつ同種間の機能の解明が必要であろう。"}]},"item_10006_dissertation_number_12":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第166号"}]},"item_10006_textarea_23":{"attribute_name":"Rights","attribute_value_mlt":[{"subitem_textarea_value":"本論文の一部は以下のとおり公表されている。(Part of this dissertation has been published as follows.) \nMurata, K., Nagasawa, M., Onaka, T., Takeyama, K., Kikusui, T. Validation of a newly generated oxytocin antibody for enzyme-linked immunosorbent assays. Journal of Veterinary Medical Science, 2021 (in press). Doi.org/10.1292/jvms.20-0723."}]},"item_10006_version_type_18":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"村田, 香織"}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2021-04-05"}],"displaytype":"detail","filename":"diss_dv_kou0166.pdf","filesize":[{"value":"1.7 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"diss_dv_kou0166","url":"https://az.repo.nii.ac.jp/record/5423/files/diss_dv_kou0166.pdf"},"version_id":"96bb49ad-6a45-4cef-9e5e-bb7281e0ab70"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2021-04-05"}],"displaytype":"detail","filename":"diss_dv_kou0166_jab&rev.pdf","filesize":[{"value":"189.4 kB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"diss_dv_kou0166_jab&rev.pdf","url":"https://az.repo.nii.ac.jp/record/5423/files/diss_dv_kou0166_jab&rev.pdf"},"version_id":"bd716385-be85-42ed-871c-99508e528577"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"doctoral thesis"}]},"item_title":"ヒト-イヌ間の絆形成におけるイヌの涙の機能に関する研究","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"ヒト-イヌ間の絆形成におけるイヌの涙の機能に関する研究"},{"subitem_title":"Research on the function of dog tears in the formation of bonds between human and dog.","subitem_title_language":"en"}]},"item_type_id":"10006","owner":"4","path":["391"],"pubdate":{"attribute_name":"公開日","attribute_value":"2021-04-05"},"publish_date":"2021-04-05","publish_status":"0","recid":"5423","relation_version_is_last":true,"title":["ヒト-イヌ間の絆形成におけるイヌの涙の機能に関する研究"],"weko_creator_id":"4","weko_shared_id":4},"updated":"2023-06-19T07:38:47.369600+00:00"}