Alóe F
Department of Neurology, University of São Paulo Medical School, Brasil.
Arq Neuropsiquiatr. 1994 Jun;52(2):273-6. doi: 10.1590/s0004-282x1994000200023.
The ubiquitousness of normal yawning and the existence of abnormal yawning warrant an understanding of this reflex. Its mechanisms and functional role are not entirely known. A review of the literature reveals that yawning is a brain stem arousal reflex with both peripheral and central loops subserving reversal of brain hypoxia or hypoxemia. Behaviorally, yawning is a semi-involuntary act that occurs also because of loss of interest in the surroundings and it is not necessarily associated with fatigue. Socio-environmental factors can influence the emergence of yawning. Dopaminergic, acetylcholinergic, ACTHergic and oxytocinergic systems are involved in the generation and modulation of yawning in animal experimentation.
正常打哈欠的普遍性以及异常打哈欠的存在，使得对这种反射的理解成为必要。其机制和功能作用尚未完全明确。对文献的回顾表明，打哈欠是一种脑干觉醒反射，其外周和中枢环路都有助于逆转脑部缺氧或低氧血症。从行为学角度来看，打哈欠是一种半自主行为，也会因对周围环境失去兴趣而发生，且不一定与疲劳相关。社会环境因素会影响打哈欠的出现。在动物实验中，多巴胺能、乙酰胆碱能、促肾上腺皮质激素能和催产素能系统都参与了打哈欠的产生和调节。
