科学家们研究“晕倒”机制已经数百年，以往总是单纯从大脑，或是心脏出发，而极少研究两者的相互作用。
近期，发表在《自然》杂志（Nature）上的研究似乎揭开了这一谜底，实验鼠在触发“晕厥机制”后立刻晕倒了。文章源自杏林事典网站杏林事典-https://www.thexiaoyuan.com/139.html
该研究声称，内脏感觉通路介导体内平衡反射，如果发生功能障碍会引起多种神经疾病，而Bezold-Jarisch反射（BJR）——一种心脏抑制反射，推测由迷走感觉神经元（VSNs）介导，会引发晕厥。文章源自杏林事典网站杏林事典-https://www.thexiaoyuan.com/139.html
该研究摘要如下：文章源自杏林事典网站杏林事典-https://www.thexiaoyuan.com/139.html
Visceral sensory pathways mediate homeostatic reflexes, the dysfunction of which leads to many neurological disorders1. The Bezold–Jarisch reflex (BJR), first described2,3 in 1867, is a cardioinhibitory reflex that is speculated to be mediated by vagal sensory neurons (VSNs) that also triggers syncope. However, the molecular identity, anatomical organization, physiological characteristics and behavioural influence of cardiac VSNs remain mostly unknown. Here we leveraged single-cell RNA-sequencing data and HYBRiD tissue clearing4 to show that VSNs that express neuropeptide Y receptor Y2 (NPY2R) predominately connect the heart ventricular wall to the area postrema. Optogenetic activation of NPY2R VSNs elicits the classic triad of BJR responses—hypotension, bradycardia and suppressed respiration—and causes an animal to faint. Photostimulation during high-resolution echocardiography and laser Doppler flowmetry with behavioural observation revealed a range of phenotypes reflected in clinical syncope, including reduced cardiac output, cerebral hypoperfusion, pupil dilation and eye-roll. Large-scale Neuropixels brain recordings and machine-learning-based modelling showed that this manipulation causes the suppression of activity across a large distributed neuronal population that is not explained by changes in spontaneous behavioural movements. Additionally, bidirectional manipulation of the periventricular zone had a push–pull effect, with inhibition leading to longer syncope periods and activation inducing arousal. Finally, ablating NPY2R VSNs specifically abolished the BJR. Combined, these results demonstrate a genetically defined cardiac reflex that recapitulates characteristics of human syncope at physiological, behavioural and neural network levels.文章源自杏林事典网站杏林事典-https://www.thexiaoyuan.com/139.html
感兴趣的读者可以在《自然》杂志看到更多信息：Nature文章源自杏林事典网站杏林事典-https://www.thexiaoyuan.com/139.html 文章源自杏林事典网站杏林事典-https://www.thexiaoyuan.com/139.html
