青い色素は，マウスの心臓の血管に嗅覚受容体（olfactory receptor 78）があることを示す。(c) Jinah Han and Anne Eichmann, Yale University
通常は鼻の中に見られる嗅覚受容体が，実は身体中の血管に存在し，血圧の調節に関与していることが明らかになった。哺乳類の腸の内側は無数の細菌で覆われており，これらの細菌が植物性食品に含まれるデンプンやセルロースを消化すると，短鎖脂肪酸（SCFA）が生じる。SCFAは腸に吸収されることで血中に到達し，血管内の嗅覚受容体Olfr78がSCFAを「嗅ぎ取る」。これにより血圧が調節されると考えられる。この血圧調節機構には他の受容体も関わっており，全体的な仕組みはまだ明らかではないが，腸内細菌が血圧の維持や調節に重要な役割を果たしていることは確かなようだ。（吉田素子）
Blood Vessels 'Sniff' Gut Microbes To Regulate Blood Pressure
Researchers at The Johns Hopkins University and Yale University have discovered that a specialized receptor, normally found in the nose, is also in blood vessels throughout the body, sensing small molecules created by microbes that line mammalian intestines, and responding to these molecules by increasing blood pressure. The finding suggests that gut bacteria are an integral part of the body’s complex system for maintaining a stable blood pressure.
A description of the research, conducted in mice and test tubes, appeared online Feb. 11 in the journal Proceedings of the National Academy of Sciences.
"The contribution that gut microbes apparently make to blood pressure regulation and human health is a surprise," says Jennifer Pluznick, Ph.D., assistant professor of physiology at the Johns Hopkins University School of Medicine. "There is still much to learn about this mechanism, but we now know some of the players and how they interact," she adds.
Pluznick says that several years ago, thanks to a "happy coincidence," she found -- in the kidney -- some of the same odor-sensing proteins that give the nose its powers. Focusing on one of those proteins, olfactory receptor 78 (Olfr78), her team specifically located it in the major branches of the kidney's artery and in the smaller arterioles that lead into the kidney's filtering structures. Olfr78 also turned up in the walls of small blood vessels throughout the body, she says, particularly in the heart, diaphragm, skeletal muscle and skin.
［単語和訳］
Blood Vessels：血管 Sniff：～の匂いを嗅ぐ Gut：消化管 Microbes：微生物 Regulate：～を調節する Blood Pressure：血圧
Researchers：研究者 specialized：特殊な receptor：受容体 small molecules：小分子 line：覆う mammalian：哺乳類の intestines：腸 bacteria：細菌 integral：不可欠の
mice：マウス test tubes：試験管 online：オンラインで Proceedings of the National Academy of Sciences：米国科学アカデミー紀要（雑誌名）
Ph.D.：博士 assistant professor：講師 physiology：生理学 interact：相互に作用する
happy coincidence：幸運な偶然の一致 kidney：腎臓 odor-sensing：匂いを感知する proteins：タンパク質 olfactory receptor：嗅覚受容体 specifically：特に arterioles：小動脈 lead into：～に入る turned up：現れた heart：心臓 diaphragm：横隔膜 skeletal muscle：骨格筋
