Faculty Collaboration Database

Breathing periodicity in intact and carotid body-denervated ponies during normoxia and chronic hypoxia. J Appl Physiol (1985) 1993 Mar;74(3):1073-82

Date

03/01/1993

Pubmed ID

8482645

DOI

10.1152/jappl.1993.74.3.1073

Scopus ID

2-s2.0-0027502854 (requires institutional sign-in at Scopus site)   14 Citations

Abstract

Periodic oscillations in pulmonary ventilation (VI), tidal volume (VT), and inspiratory and expiratory times (TI and TE) were studied during normoxia (arterial PO2 = 95 Torr) and 48 h of hypoxia (arterial PO2 = 40-50 Torr) in awake intact (n = 8) and carotid body-denervated (CBD; n = 8) ponies. Periodic oscillations were identified by fast-Fourier transformation of breath-by-breath data and quantitated by determining the power ratio of significant periodic oscillations to total power of data sequence. Periodic oscillations of 0.063-0.500 cycles/breath were observed in all parameters during both normoxia and hypoxia. During normoxia, CBD accentuated periodicity of VT (P < 0.02) and VI (P < 0.01) but did not change TI or TE periodicity (P > 0.05). These findings suggest that carotid chemoreceptors serve to stabilize breathing (i.e., decrease periodicity) during normoxia, conceivably because of their shorter response time compared with that of central chemoreceptors. During certain periods of hypoxia, periodicity of VT and VI was significantly (P < 0.05) increased in intact ponies. The response to hypoxia in CBD ponies was variable, with VI periodicity significantly (P < 0.05) increasing, decreasing, or unchanging. Because some CBD ponies significantly changed their periodicity during hypoxia compared with normoxia, we conclude that carotid chemoreceptors are not requisite for hypoxia-induced changes in periodic breathing. In addition, our observations in both groups of ponies during normoxia and hypoxia suggest that multiple mechanisms may lead to periodic oscillations in breathing.

Author List

Brown DR, Forster HV, Greene AS, Lowry TF

Author

Hubert V. Forster PhD Professor in the Physiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Arousal
Carbon Dioxide
Cardiography, Impedance
Carotid Body
Chemoreceptor Cells
Chronic Disease
Denervation
Electroencephalography
Fourier Analysis
Horses
Hydrogen-Ion Concentration
Hypoxia
Oxygen
Respiratory Mechanics