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Arquivos de Neuro-Psiquiatria

Print version ISSN 0004-282X

Arq. Neuro-Psiquiatr. vol.52 no.2 São Paulo June 1994 






Flávio Alóe

Sleep-Wake Disordes Center, Department of Neurology of the University of São Paulo Medical School




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.

Key words: yawning, fatigue, drowsiness, brain hypoxia, dopamine, acetylcholine, ACTH, oxytocin.


A ubiquidade do bocejo normal e a existência de bocejo de caráter anormal justificam o conhecimento deste reflexo. Muito pouco se sabe a respeito dos mecanismos fisiológicos e papel funcional dos bocejos. Uma revisão da literatura mostra que o bocejo é um reflexo de alerta cerebral com alças centrais e periféricas, cujo objetivo é reverter hipoxia ou hipoxemia cerebral. Comportamentalmente, bocejar é ato semi-involuntário que ocorre também por causa de perda cognitiva de interesse pelo meio ambiente e não está necessariamante associado com sensação de fadiga. Fatores sócio-ambientais podem influenciar o aparecimento de bocejos. Os sistemas neuronais dopaminérgico, colinérgico, ACTH e oxitocinérgico estão envolvidos na geração e modulação do bocejo em animais de experimentação.

Palavras-chave: bocejo, fadiga, hipoxia, sonolência, dopamina, acetilcolina, ACTH, oxitocina.



Texto completo disponível apenas em PDF.

Full text available only in PDF format.



Acknowledgments - Special thanks to Dr. Stella Tavares and Dr. Leticia Lobo for their assistance.



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Aceite: 22-novembro-1994.



Dr. Flávio Aloé - Al. Jaú 1791 - 01420-002 São Paulo SP - Brasil. FAX (55.11) 280-9519.

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