O-2 CHEMOREFLEX DRIVE OF VENTILATION IN AWAKE RAT

  • 1 January 1978
    • journal article
    • research article
    • Vol. 74  (4) , 411-417
Abstract
Resting ventilation, arterial pH and gas tensions in the arterial blood and ventilatory responses to transient O2 inhalation were studied by plethysmography, under normoxic and hypoxic (FIO2 [concentration of O2 in inspired gas] = 0.12) conditions, in the awake rat before and after chronic bilateral denervation of the carotid bodies. In the intact rat, the O2-chemoreflex drive of ventilation controlled about 50% of the normoxic minute volume and 85% in hypoxia. Chronic bilateral carotid body denervation reduced the chemoreflex drive to 1/2, and was accompanied by a hypoventilation with arterial hypercapnia. In acute hypoxia hyperventilation was reduced in carotid-body denervated animals, and was accompanied by a light respiratory insufficiency. The rat apparently has a powerful arterial chemoreflex drive of breathing which is essential in determining the eupneic level of ventilation in acute hypoxia.