In:
Journal of Applied Physiology, American Physiological Society, Vol. 97, No. 4 ( 2004-10), p. 1401-1407
Abstract:
We examined the effects of carotid body denervation on ventilatory responses to normoxia (21% O 2 in N 2 for 240 s), hypoxic hypoxia (10 and 15% O 2 in N 2 for 90 and 120 s, respectively), and hyperoxic hypercapnia (5% CO 2 in O 2 for 240 s) in the spontaneously breathing urethane-anesthetized mouse. Respiratory measurements were made with a whole body, single-chamber plethysmograph before and after cutting both carotid sinus nerves. Baseline measurements in air showed that carotid body denervation was accompanied by lower minute ventilation with a reduction in respiratory frequency. On the basis of measurements with an open-circuit system, no significant differences in O 2 consumption or CO 2 production before and after chemodenervation were found. During both levels of hypoxia, animals with intact sinus nerves had increased respiratory frequency, tidal volume, and minute ventilation; however, after chemodenervation, animals experienced a drop in respiratory frequency and ventilatory depression. Tidal volume responses during 15% hypoxia were similar before and after carotid body denervation; during 10% hypoxia in chemodenervated animals, there was a sudden increase in tidal volume with an increase in the rate of inspiration, suggesting that gasping occurred. During hyperoxic hypercapnia, ventilatory responses were lower with a smaller tidal volume after chemodenervation than before. We conclude that the carotid bodies are essential for maintaining ventilation during eupnea, hypoxia, and hypercapnia in the anesthetized mouse.
Type of Medium:
Online Resource
ISSN:
8750-7587
,
1522-1601
DOI:
10.1152/japplphysiol.00025.2004
Language:
English
Publisher:
American Physiological Society
Publication Date:
2004
detail.hit.zdb_id:
1404365-8
SSG:
12
SSG:
31
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