Scientists have shown that 環境の stress can affect normal development of 神経質な system in worms who are approaching puberty
Scientists have been trying to understand how our genes (our genetic makeup) and different 環境の factors shape our 神経系 私たちが成長していく発達初期の時期。 この知識により、主に神経系の正常な神経回路が崩壊したときに引き起こされるさまざまな神経障害についての理解が深まります。 で発表された研究では、 自然, 科学者たち from Columbia University have studied the nervous system of small transparent worms (線虫) to elucidate understanding of how it shapes up. They show that stress caused by environmental factors can have a permanent intense effect on connections taking place in the nervous system which is still developing. In their experiment they made male worms undergo starvation just before the worms were to undergo sexual maturation with an aim to stunt their puberty. Exposure to external stress, specifically starvation, even a few days before sexual maturation affected wiring patterns of critical neuronal circuits in worm’s 神経質な system thus preventing normal changes to take place. The rewiring program of their nervous system was basically interrupted. Once these ‘強調’ males underwent puberty and became adult, immature circuits still remained in their nervous system causing them to continue to act immature. Their Immaturity was judged by observing that stressed adult male worms showed high sensitivity to a toxic chemical called SDS compared to normal adult males. The stressed worms also spent limited time with other hermaphrodite worms and had difficulties in mating.
科学者たち made this crucial discovery when some worms were accidently left unattended for some weeks and not given food. This led to a pause in worms’ normal development and they entered a state called ‘dauer state’. This state is like a temporary halt in normal growth of an organism. In case of worms, when immature worms sensed any type of stress, a temporary pause happens in their normal growth for months and later once the stress is gone their growth resumes. So, after stress of starvation passed, worms returned to their normal environment and they went on to mature into adults. Upon examining the nervous system of now adult worms, it was seen that some immature connections in male worm’s tails were retained which would ideally have been eliminated (or pruned) during sexual maturation. Researchers investigated further to state that ‘dauer state’ was caused exclusively by stress of starvation and not by any other form of stress. The stress led to remapping of their wire diagrams. The opposite effects of two neurotransmitters – serotonin and octopamine – control pruning of circuits. The stressed worms had high amount of octopamine which then blocked production of serotonin. If serotonin was given to immature males during stress, then normal pruning took place and adults start exhibiting mature reaction to SDS. In comparison when octopamine was given to immature males, this prevented the circuit pruning. Study suggests that stress can have a likely effect on changes in nervous system when 早く development is taking place. The neurotransmitter serotonin is associated with mental condition of depression in humans.
この可能性は人間にも当てはまるのでしょうか？ 人間は動物に比べてはるかに大きく複雑な神経系を持っているため、これは簡単ではありません。 それにもかかわらず、線虫は神経系を研究および分析するための単純だが効率的なモデル生物です。 この研究の主任研究者らは、ceNGENと呼ばれるプロジェクトを開始した。これにより、C.エレガンスの神経系における各ニューロンの遺伝子構成と活動をマッピングすることで、神経系の成り立ちをより詳細に理解し、神経系間の協力の可能性を理解するのに役立つだろう。遺伝子構造と個人の経験。
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ソース
Bayer EA および Hobert O. 2018。過去の経験が、モノアミン作動性シグナル伝達を介して性的二形性の神経配線を形成します。 自然. https://doi.org/10.1038/s41586-018-0452-0
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