Fung M L, St John W M
Department of Physiology, Dartmouth Medical School, Lebanon, NH 03756, USA.
Respir Physiol. 1995 May;100(2):119-27. doi: 10.1016/0034-5687(94)00128-m.
The purpose was to characterize expiratory neural activities in gasping elicited during the aspiration reflex (AR) in hyperoxia and during hypoxia-induced gasping. In decerebrate, vagotomized and paralyzed cats, we recorded activities of inspiratory and expiratory cranial and spinal nerves. The AR was elicited by touching the epipharyngeal mucosa. In eupnea, spinal expiratory activities were greatly decreased during AR whereas laryngeal expiratory activities were increased. In hypoxia-induced gasping, both the laryngeal and spinal expiratory activities were reduced. All of the inspiratory activities were increased during both gasping and the AR. In addition, neural activities were below control levels following AR; activities gradually recovered to control levels. We conclude that spinal expiratory activities are inhibited during the AR and gasping. Results are consistent with the concept that medullary mechanisms for gasping are recruited by mechanical stimulation of the epipharynx. In hypoxia-induced gasping, the hypoxia, per se, causes a separate suppression of laryngeal expiratory activities.
目的是对高氧时吸气反射（AR）诱发的喘息以及低氧诱导的喘息过程中的呼气神经活动进行特征描述。在去大脑、切断迷走神经并麻痹的猫身上，我们记录了吸气和呼气的颅神经及脊神经活动。通过触碰咽上黏膜诱发AR。在平静呼吸时，AR期间脊髓呼气活动大幅减少，而喉部呼气活动增加。在低氧诱导的喘息中，喉部和脊髓呼气活动均减少。在喘息和AR期间，所有吸气活动均增加。此外，AR后神经活动低于对照水平；活动逐渐恢复到对照水平。我们得出结论，在AR和喘息期间脊髓呼气活动受到抑制。结果与以下概念一致，即喘息的延髓机制是由咽上的机械刺激募集的。在低氧诱导的喘息中，低氧本身会单独抑制喉部呼气活动。
