O'Halloran K D, Curran A K, Bradford A
Dept of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin at Madison, USA.
Eur Respir J. 1998 Jul;12(1):177-84. doi: 10.1183/09031936.98.12010177.
The cervical sympathetic trunks innervate the carotid bodies, carotid baroreceptors, thyroid gland and the upper airway mucosa, structures which can influence breathing and upper airway resistance. However, their role in the control of ventilation and upper airway patency is poorly understood. A constant airflow was applied to the upper airway through a high-cervical tracheostomy in anaesthetized rats breathing spontaneously through a low-cervical tracheostomy. The peripheral ends of the cut cervical sympathetic trunks were stimulated electrically and airflow resistance and ventilation were measured. The effects of cervical sympathetic trunk section on ventilation were also measured in conscious rats. In conscious rats, cutting the sympathetic trunks caused a decrease in ventilation during normoxia but only slightly affected ventilatory responses to hypoxia and hypercapnia. In anaesthetized rats, sympathetic trunk stimulation caused an inhibition of breathing which was sometimes followed by excitation. These responses were unaffected by alpha- or beta-adrenoceptor blockade but were abolished by cutting the carotid sinus nerves. Sympathetic stimulation also caused a fall in upper airway resistance which was reduced by bypassing the nose, unaffected by propranolol or carotid sinus nerve section and abolished by phentolamine. It was concluded that the cervical sympathetic nerves exert important influences on ventilation and upper airway resistance.
颈交感干支配颈动脉体、颈动脉压力感受器、甲状腺和上呼吸道黏膜，这些结构可影响呼吸和上呼吸道阻力。然而，它们在控制通气和上呼吸道通畅方面的作用尚不清楚。在通过低位颈段气管造口进行自主呼吸的麻醉大鼠中，通过高位颈段气管造口对上呼吸道施加恒定气流。对切断的颈交感干的外周端进行电刺激，并测量气流阻力和通气情况。还在清醒大鼠中测量了颈交感干切断对通气的影响。在清醒大鼠中，切断交感干在常氧期间导致通气减少，但仅轻微影响对低氧和高碳酸血症的通气反应。在麻醉大鼠中，交感干刺激导致呼吸抑制，有时随后出现兴奋。这些反应不受α或β肾上腺素能受体阻断的影响，但通过切断颈动脉窦神经而消除。交感刺激还导致上呼吸道阻力下降，通过绕过鼻子可降低该阻力，不受普萘洛尔或颈动脉窦神经切断的影响，而酚妥拉明可消除该影响。得出的结论是，颈交感神经对通气和上呼吸道阻力有重要影响。
