日本熊本大學一個研究小組在《自然—神經(jīng)科學》雜志網(wǎng)絡版上發(fā)表報告說,，實驗發(fā)現(xiàn)在果蠅的腦內(nèi)，睡眠和記憶這兩種行為,，是被完全獨立的兩個神經(jīng)回路所控制,。
據(jù)研究人員介紹，神經(jīng)傳遞物質(zhì)多巴胺在睡眠和記憶過程中發(fā)揮重要作用,，但這種物質(zhì)的作用機制一直以來都是個謎,。
在實驗中，研究人員首先通過基因操作,，在果蠅腦內(nèi)稱為扇形體的部位形成多巴胺受體,。結果，多巴胺發(fā)揮作用后,，果蠅的睡眠時間減少,，也就是說，扇形體是果蠅的睡眠中樞,；在另一組實驗中,，研究人員在果蠅腦內(nèi)已知與記憶有關的蘑菇體內(nèi)制作相同受體，果蠅的睡眠卻沒有發(fā)生變化,。這表明,，果蠅的睡眠和記憶是分別由各自獨立的神經(jīng)回路所控制。
此外,，實驗結果還顯示,，果蠅腦內(nèi)的扇形體和蘑菇體會分別與其他神經(jīng)細胞釋放的多巴胺發(fā)生反應。
領導這項研究的熊本大學副教授粂和彥說,，這一新發(fā)現(xiàn)有助研究人員找到新途徑,，向睡眠中的腦部輸入信息，未來將有可能實現(xiàn)在睡眠中學習,。（生物谷Bioon.com）
doi:10.1038/nn.3238
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Identification of a dopamine pathway that regulates sleep and arousal in Drosophila
Taro Ueno, Jun Tomita, Hiromu Tanimoto, Keita Endo, Kei Ito, Shoen Kume, & Kazuhiko Kume
Sleep is required to maintain physiological functions, including memory, and is regulated by monoamines across species. Enhancement of dopamine signals by a mutation in the dopamine transporter (DAT) decreases sleep, but the underlying dopamine circuit responsible for this remains unknown. We found that the D1 dopamine receptor (DA1) in the dorsal fan-shaped body (dFSB) mediates the arousal effect of dopamine in Drosophila. The short sleep phenotype of the DAT mutant was completely rescued by an additional mutation in the DA1 (also known as DopR) gene, but expression of wild-type DA1 in the dFSB restored the short sleep phenotype. We found anatomical and physiological connections between dopamine neurons and the dFSB neuron. Finally, we used mosaic analysis with a repressive marker and found that a single dopamine neuron projecting to the FSB activated arousal. These results suggest that a local dopamine pathway regulates sleep.
