Yawning.
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.
Alóe
F
F
Department of Neurology, University of São Paulo Medical School, Brasil.
D000818:Animals; D006801:Humans; D010121:Oxytocin / Q000494:pharmacology; D051381:Rats; D012018:Reflex / Q000502:physiology; D015000:Yawning / Q000502:physiology*
D010121:Oxytocin