A cluster of hormone-producing cells identified that is activated by anaesthetics
Despite general anaesthetics having been used since the middle of the 19th century, doctors have never known the exact mechanism by which they work. A prevailing notion was that the drugs led to a widespread shutting down of brain cell activity. But recent work shows that there's also a key part of the brain that general anaesthetics activate: the supraoptic nucleus – a cluster of hormone secreting cells (stained red in the slice of mouse brain pictured). By using a genetic technique that allows cells to be instantly stimulated by light (optogenetics), researchers found that activating this cell cluster caused awake mice to stop moving and fall into a deep sleep akin to unconsciousness. Elimination of the cells, by contrast, prevented sleep. The identification of this anatomical mediator of general anaesthetics could lead to the development of better drugs – for both anaesthesia and sleep – with fewer unpleasant side effects.
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