生物谷報(bào)道：美國科學(xué)家近日發(fā)現(xiàn)除了光線以外,，進(jìn)食也可以調(diào)節(jié)生物鐘,，這一發(fā)現(xiàn)有助于解釋動(dòng)物怎樣調(diào)節(jié)生理節(jié)奏以避免餓死,，并且表明，通過調(diào)節(jié)進(jìn)食時(shí)間,，人類能夠更好地應(yīng)對(duì)時(shí)差和夜間工作,。相關(guān)論文發(fā)表在23日的《科學(xué)》雜志上。
在動(dòng)物大腦的視丘下部,，有一組名為視交叉上核（SCN）的細(xì)胞,，起著機(jī)體主生物鐘的作用,。SCN經(jīng)由視覺系統(tǒng)接收日-夜循環(huán)的信號(hào)，并將信號(hào)傳遞給視丘下部的另一組名為背內(nèi)側(cè)核（DMH）的細(xì)胞,，DMH接著組織起眠-覺循環(huán),，以及活動(dòng)、進(jìn)食,、荷爾蒙循環(huán),。研究人員稱當(dāng)食物容易獲得的時(shí)候，這一系統(tǒng)運(yùn)轉(zhuǎn)得極其順利,，光信號(hào)幫助動(dòng)物建立了適應(yīng)標(biāo)準(zhǔn)日-夜循環(huán)的生理節(jié)奏,。然而，如果食物在正常的覺醒期間無法獲得,，動(dòng)物就需要能夠適應(yīng)在常規(guī)睡眠期間獲得食物,。為了生存下來，動(dòng)物發(fā)展出了第二種“食物相關(guān)”的時(shí)鐘,。這一新的時(shí)鐘使動(dòng)物能夠轉(zhuǎn)變它們睡眠和覺醒的時(shí)間表,，以有最大化發(fā)現(xiàn)食物的機(jī)會(huì)。
在實(shí)驗(yàn)中,，研究人員使用滅活了生物鐘關(guān)鍵基因（BMAL1）的小鼠為實(shí)驗(yàn)對(duì)象,，然后將這一基因置入病毒載體，達(dá)到了一次只在大腦中一個(gè)地點(diǎn)恢復(fù)生物鐘功能的目的,。通過這種按部就班的分析,，研究人員揭示了與進(jìn)食有關(guān)的生物鐘。研究發(fā)現(xiàn),，在饑餓循環(huán)后喂食能開啟生物鐘,，所以它有效地越過了SCN，并將所有的生理節(jié)奏‘劫持’到了一個(gè)新的時(shí)區(qū),，與食物獲取相一致,。
研究人員表示，這一發(fā)現(xiàn)有望在旅行者和倒班工作者身上得到應(yīng)用,。比如,，旅行者可以通過改變進(jìn)食時(shí)間，使自己的進(jìn)食時(shí)鐘開始運(yùn)轉(zhuǎn),，從而能更快地調(diào)整時(shí)差。完全禁食16個(gè)小時(shí)足以開啟這一新的時(shí)鐘,。所以,，在飛機(jī)上不吃任何食物，著陸后盡快進(jìn)食,，將能夠幫助你調(diào)節(jié)時(shí)差,，并能避免一些不舒服的時(shí)差反應(yīng),。（生物谷www.bioon.com）
生物谷推薦原始出處：
Science，Vol. 320. no. 5879, pp. 1074 – 1077,，Patrick M. Fuller,，Clifford B. Saper
Differential Rescue of Light- and Food-Entrainable Circadian Rhythms
Patrick M. Fuller, Jun Lu, Clifford B. Saper*
When food is plentiful, circadian rhythms of animals are powerfully entrained by the light-dark cycle. However, if animals have access to food only during their normal sleep cycle, they will shift most of their circadian rhythms to match the food availability. We studied the basis for entrainment of circadian rhythms by food and light in mice with targeted disruption of the clock gene Bmal1, which lack circadian rhythmicity. Injection of a viral vector containing the Bmal1 gene into the suprachiasmatic nuclei of the hypothalamus restored light-entrainable, but not food-entrainable, circadian rhythms. In contrast, restoration of the Bmal1 gene only in the dorsomedial hypothalamic nucleus restored the ability of animals to entrain to food but not to light. These results demonstrate that the dorsomedial hypothalamus contains a Bmal1-based oscillator that can drive food entrainment of circadian rhythms.
Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
* To whom correspondence should be addressed. E-mail: [email protected]
