There are some animals which live in the high-altitude and cold environments. To learn how the wild animals adapt to and survive in such extreme environments is an important and useful approach not only for the progress of science but also for health promotion and prosperity of the human. The , Ochotona, living in cold zone or in high mountains prefers the low temperatures and is considered to be remained species of the glacial periods. The 's high body temperature, high metabolic rate and high fur insulation are advantageous for survival in the cold. The 's unique behavioral strategies to adapt to cold are living in burrows under the ground or in the shelter among rocks and hoarding grasses for winter foods. The do not hibernate, though many mammals living nearby hibernate. On the other hand, the is heat intolerant due to poor heat loss ability such as poor panting, small ear pinnae and the absence of thermal salivation. The pikas reared in the laboratory showed neither diurnal nor nocturnal body temperature rhythm. Our fieldwork using bio-telemetry devices in their natural habitat in Qinghai, China demonstrated that the pikas are essentially diurnal. Taking the ecologists' field observation together into consideration, it is suggested that the pikas may vary their activity rhythm from diurnal in the relatively cool environment to a crepuscular (dawn and dusk) pattern in the relatively hot environment to avoid the heat during midday. The is also of interesting because of its communication with calls and its territorial social organization. [Jpn J Physiol 55 Suppl:S65 (2005)]

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Uncoupling protein 1 (UCP1) is present exclusively in brown adipose tissue, and contributes to body temperature control during cold exposure. We cloned UCP1 cDNA of plateau (Ochotona dauurica), a small, non-hibernating, diurnal lagomorph that inhabits in relatively cold climates and at high altitudes in Mongolia and in northern China. The nucleotide sequence of UCP1 was highly homologous to UCP1 of other species, and the deduced amino acid sequence had some common domains for UCP, including six mitochondrial carrier protein motifs and a putative purine-nucleotide binding site. RT-PCR and Western blot analyses revealed that both UCP1 mRNA and protein were expressed exclusively in the interscapular adipose tissue. These results suggest that UCP1 contributes to heat production in brown adipose tissue, as do those in other species.

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Morphological changes in the cecal mucosa from the late fetal stage to the adult stage were observed mainly by scanning electron microscopy and were compared with those of the rabbit. The cecal mucosa of both the rabbit and the could always be divided into two portions, that is, a protruded region and a basal region.
The basal region of the cecum showed a similar morphological change to that of the rabbit cecum in that the basal regions of both the and the rabbit were covered with columnar or round villi from the late fetal stage to 5 days after birth. After 10 days, villi disappeared and as a result their basal regions exhibited irregular short ridges.
By contrast, the protruded region of the cecum showed a different developmental process from that of the rabbit cecum. The protruded region of the rabbit showed a fold at 25 days of gestation and developed progressively in accordance with age to form the spiral fold. In the cecum, the protruded region also revealed a fold at the late fetal stage, but the fold divided into many hump-like protrusions after birth and formed cecal digitations at 5 days after birth. After 5 days, the cecal digitations were gradually transformed from a short columnar to a long columnar shape and finally to a flat slender form at the adult stage.

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実験動物化されたナキウサギに, 反芻獣由来消化管内寄生線虫を感染させたところ, Haemonchus contortus, Ostertagia circumcincta, Trichostrongylus axei, T. colubriformisで感染が成立した。T. axeiとT. colubriformisは感染率が高く, 感染後70日でもpatent infectionが持続し, spontaneous cureは見られなかった。O. circumcinctaは, 感染後20日に剖検したナキウサギから虫卵を保有した雌2虫体が回収されただけであった。H. contortusは, 感染率は低いながらも感染後20日までは回収されたが, 感染後45日以降は回収されなかった。また, 回収された虫体はすべて未成熟であった。Strongyloides papillosus, Bunostomum trigonocephalum, Chabertia ovina, Mecistocirrus digitatusは, 感染が成立しなかった。

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The blue-sheep, , and yak live in the Tibetan highlands at an altitude of 6,100 m and are typical mammals adapted to high-altitudes. These animals have a long history of habitation at high-altitudes and are considered to be "animals completely adapted to high-altitudes" because of their physiological and morphological traits that are well adapted to high-altitude environments. To evaluate the physiological characteristics of high-altitude adaptation in the blue-sheep, changes in the pulmonary hemodynamics during exposure to simulated-altitudes at 0, 2,300, and 4,500 m were examined by means of a climatic chamber in Qinghai Province, China (altitude 2,300 m). Seven blue-sheep inhabiting the mountains (3,000 m) of Qinghai Province, China, were compared with 5 pigs raised in the same area as controls. The primary items of measurement were the body weight (BW), systemic arterial pressure (Psa), pulmonary artery pressure (Ppa), hematocrit (Ht), left ventricular weight (LVW), right ventricular weight (RVW), and blood gas profile. The principal findings of this study are: (1) Ht, an index of right ventricular hypertrophy (RVW/LVW), and oxygen consumption (V˙O₂) were significantly lower in the blue sheep compared with the pigs; (2) When the animals were exposed to simulated-altitudes at 0, 2,300, and 4,500 m, Ppa increased significantly in tandem with altitude elevation in both species, but the increases were significantly smaller in the blue-sheep; and (3) Ppa/Psa, an index of the right ventricular load, increased with the altitude in both species, but the increases were smaller in the blue sheep. From these observations, low Ht and RVW/LVW and significant attenuation of hypoxic pulmonary vasoconstriction (HPV) in the blue-sheep is considered to be characteristics of animals completely adapted to high-altitudes, such as the .

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ナキウサギ(Ochotona rufescens rufescens)の脾臓の一般構築を光学ならびに電子顕微鏡的に観察し, ナキウサギ脾臓における微細血管走行を明らかにするため, その合成樹脂鋳型標本を走査電子顕微鏡で観察した。脾臓の基本的細胞成分および血管系はイエウサギのそれに類似していたが, 成熟した個体においても, 脾索に活発な髄外造血が認められ, 特徴ある所見を呈していた。また, ナキウサギ脾臓においては, 縁洞壁の構造が脾洞壁と同様に有窓状であることが注目された。鋳型標本を走査電顕で観察すると, 縁帯では閉鎖および開放循環の双方が, また赤脾髄では開放循環のみが示唆された。合成樹脂あるいはカーボン粒子を静脈内に注入すると, これらは最初に縁洞壁から漏出するところから, 縁洞の機能は異物あるいは抗原性物質に対する濾過装置的なものと思われた。

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The proximal colon in three species of lagomorph macroscopically consisted of three segments. The first segments of the domestic and volcano rabbits each were divided into two portions (anterior and posterior parts), while the same region of the into three portions (small haustra side, anterior and posterior parts of large haustra side). The anterior part mucosa of the two former species showed low curved folds and no mucous glands. The posterior part mucosa of the domestic rabbit exhibited cauliflower-like protrusions, while that of the volcano rabbit showed multi-formed protrusions. Mucous glands exist in all species examined from the posterior part to the distal colon. The anterior part mucosa of the revealed an almost flat appearance and no mucous glands. The posterior part mucosa and the small haustra in the exhibited conical protrusions with mucous glands. Although the second segment of the domestic rabbit revealed cauliflower-like protrusions, those of the volcano rabbit and the exhibited villus-like protrusions. The third segment and the distal colon of each species similar showed the feature with flat surface.

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The morphological changes in the ampulla coli, especially the net-arranged folds, from the late fetal stage to the adult stage were examined by the naked eye, light microscopy and scanning electron microscopy.
At 25 days of gestation, the ampulla coli could already be discerned from the cecum and the proximal colon by the lack of haustra. In addition to the well-developed muscular coat, the ampulla coli at this stage was provided with a number of short columnar viii. Although the mucosal surface of the ampulla coli was filled with villi until 3 days after birth, a drastic change occurred at 5 days. That is, the villi gathered together at regular intervals and, as a result, the ampulla coli mucosa revealed a net-arranged appearance at 5 days. At 10 days, the villi disappeared completely and net-arranged folds, derived from the gathered villi at 5days, covered the ampulla coli mucosa. After 15 days, small villus-like protrusions on the lateral side of the folds developed secondarily and gradually grew in height in accordance with age. At the adult stage, the ampulla coli was overspread with net-arranged folds equipped with small villus-like protrusions.

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北海道大雪山系で捕獲され, 帯広動物園で飽育されていたニホンナキウサギの肺に認めたCrysosporiumによる病変について病理組織学的に検索した. 病変部に認めた直径300～420μmのadiasporeは, その大きさ, 構造および染色性から, これまで多くの野生小型哺乳動物の肺に報味されてきたC.parvum var. crescensによるadiaspiromycosisのそれに一致し, ニホンナキウサギにおける本病の存在が明らかになった.

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ナキウサギの腸管各部を肉眼, 光顕および走査電顕で観察し, カイウサギ (日本白色種) のそれらと比較検討した。カイウサギの十二指腸粘膜はヒダ構造でおおわれるが, ナキウサギでは葉状ないし円柱状の絨毛からなる。しかし回腸では両者とも円柱状の絨毛が存在する。ナキウサギの回盲口付近には回盲口部虫垂とよばれる特異的なリンパ装置が発達し, 結腸への移行部においては筋層が厚く発達した狭窄部とよばれる特有の部位が認められる。狭窄部の粘膜表面は網目状のヒダ構造を示し, ヒダの側面には多数の絨毛様小突起が存在する。またカイウサギの盲腸粘膜にはラセン状に走る盲腸ラセン弁が認められるのに対し, ナキウサギではラセン弁は存在せず, 代わりに細長い小突起 (盲腸指状突起) が盲腸膨起間の溝の部分から輪状に突出している。結腸近位部以下では両者とも3本さらに1本の結腸ヒモをもつ部位が順に続いた後, 結腸ヒモのない部位へと移行している。結腸ヒモ3本の部位ではナキウサギの粘膜表面には多くの小突起があり, その粘膜固有層中には粘液腺が存在するのに対し, カイウサギではいずれも認められない。結腸ヒモ1本の部位ではナキウサギの粘膜表面は絨毛様隆起におおわれるが, カイウサギではコブ状隆起が連続している。この部位では両者とも固有層中に粘液腺をもつ。結腸ヒモのない部位では両者とも粘膜面は比較的平坦で, 固有層中には直腸に至るまで粘液腺が観察される。

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23研究機関の協同研究として, 従来ヒト, ラット, マウス, ウサギのいずれかに催奇形性を示すとされた15種の薬物, 即ちcyclophosphamide, 6-mercaptopurine, 5-fluorouracil, 6-aminonicotinamide, actinomycine D, ethylurethan, ampicillin, tetracycline, thalidomide, diphenylhydantoin, vitamin A過剰, aspirin, dexa-methasone, betamethasone, bredininを取り上げ, それぞれを妊娠ナキウサギの器官形成期に投与し, どの程度の催奇形性を示すかを検索した。その成績を総括すると, 先ずナキウサギに於て一定の薬物 (cyclophosphamide, 6-aminonicotinamide, vitamin A 過剰, bredinineなど) が奇形の誘発を来した。しかしナキウサギに於ては, ラット, マウス, ウサギに比べ, 奇形に関する感受性の低い場合の多いことが知られた。なお典型的なサリドマイド症候群は示されなかった。
ナキウサギは小型で, 習熟すれば取扱い易くなるもので, また繁殖力は良好であり, 従って必要により催奇形性試験の新動物種として加えられてもよいものと考えられた。

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ナキウサギOchotona rufescens rufescensが新しい皮膚刺激性試験動物として供試可能か否かを検討するため, 皮膚の組織構造および酵素組織化学反応を調べた。ナキウサギは, ウサギと同様にヘアーサイクルを有していた。ナキウサギの体幹部の皮膚および表皮の厚さは, 各々平均1.16mmおよび29.5μmであり, いずれも背部で最も厚く, ついで肩甲間部で, 逆に腹部は最も薄かった。ナキウサギの表皮の角質層, 果粒層, 有棘細胞層, 基底層は比較的明瞭に区別され, 基底層の細胞配列はウサギに比べて緻密であった。皮膚肥満細胞の分布は, ウサギおよびモルモットと異なり, ナキウサギでは表皮直下の真皮乳頭層であった。ナキウサギの肥満細胞のTEM像は, 果粒の電子密度が低く, 微繊毛様突起およびミトコンドリアが比較的大きかった。毛嚢および皮脂線でのSDH, MDH, LDH, βHBDH, αGPDH, ALD, G6PDHおよびGPRの各酵素活性は, ナキウサギとウサギの間で大差は見られなかった。

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Many people prefer products made with natural rather than artificial materials, and favor luxury products with high social value. In this study, we examined whether similarities and differences between “naturalness” and “luxuriousness” manifested in the onomatopoeic expressions used in texture evaluation. We used pearls and gold leaf, which have different market values depending on grade. Participants were asked to visually evaluate the “naturalness” and “luxuriousness” of these items through a semantic differential technique and onomatopoeic expressions. We found that it was difficult for non-experts to distinguish which item actually had the highest value, but there was a positive correlation between “naturalness” and “luxuriousness” perceptions. Regarding the onomatopoeia results, when a material was perceived as artificial, participants described its texture with visual onomatopoeia. However, when the material was perceived as natural, tactile as well as visual onomatopoeias were used to describe texture. Based on these results, we suggest that knowledge based on of tactile experience may have influenced the visual perception of “naturalness” and “luxuriousness.”

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ナキウサギおよびメキシコウサギの耳下腺の腺胞, 介在部および線条部について光学顕微鏡ならびに透過電子顕微鏡で観察した。ナキウサギおよびメキシコウサギの腺胞は, 両者ともに漿液細胞からなり, 前者には微塩基好性を示す電子密度の低い分泌顆粒を持つ明調細胞が, 後者には酸好性を示す種々の分泌顆粒を持つ明調細胞と少数の暗調細胞が認められた。介在部上皮細胞は両者ともに同様の構造を示し, 明調細胞のみからなり, 核上部から頂部にかけて電子密度中程度の顆粒を有していた。線条部上皮細胞は両者ともに明調細胞と少数の暗調細胞からなり, ナキウサギにおいては, 頂部に少数の電子密度中程度の顆粒を有していた。両者ともに, 筋上皮細胞は腺胞, 介在部および線条部のいずれの部位にも認められなかったが, 神経終末は腺胞細胞間および腺胞細胞と基底板との間に認められた。

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