Loss of peripheral chemoreflexes to hypoxia after carotid body removal in the rat.

Young Sprague-Dawley female rats (16-18 days old) were subjected to bilateral carotid glomectomy or the sham operation under halothane anaesthesia. After recovery, the rats were placed with non-operated peers. One to six months later glomectomised, sham-operated and control animals were anaesthetized with sodium pentobarbital. Respiratory minute volume and arterial pressure were recorded. Respiratory responses to few-breath administration of oxygen or nitrogen, and arterial pressure responses to carotid occlusion or tugging were tested. Oxygen produced transient hypoventilation and nitrogen transient hyperventilation in control, sham and 3 of 31 glomectomised rats. Bilateral vagotomy did not abolish these responses. In only those 3 glomectomised rats was carotid glomus tissue histologically identifiable. Carotid occlusion raised and tugging lowered arterial pressure in all animals. Glomectomy did not affect serum levels of GH, FSH, LH or PRL hormones but produced right ventricular hypertrophy. We conclude that peripheral chemoreception requires the presence of glomus tissue.