TY - JOUR
T1 - Baroreceptor output during normal and obstructed breathing and Mueller maneuvers
AU - Fitzgerald, R. S.
AU - Robotham, J. L.
AU - Anand, A.
PY - 1981
Y1 - 1981
N2 - Cardiovascular control during asthma and other forms of obstructed breathing has not been extensively investigated. Previous studies in dogs have shown that obstructed breathing or an inspiratory effort against a blocked airway (Mueller maneuver) provoke large oscillations in blood pressure. During the inspiratory phase transmural systolic pressure relative to atmosphere drops initially, but transmural systolic pressure relative to intrathoracic pressure can remain unchanged or even increase. Because the carotid baroreceptors are located in the extrathoracic circulation, whereas the aortic baroreceptors are located in the intrathoracic circulation, and each responds to local transmural arterial pressure, simultaneous baroreceptor output from these 2 areas was measured in the anesthetized cat during normal and obstructed breathing and during Mueller maneuvers. Both whole-nerve and single-fiber preparations showed a significantly decreased output from the carotid baroreceptors during obstructed inspiratory efforts, whereas aortic baroreceptor output decreased significantly less or not at all. Transmural systolic pressure decreased significantly less in the aorta than in the carotid regions. Further, the aortic baroreceptors were more sensitive to changes in pulse pressure than were the carotid baroreceptors. These results suggest a mechanism for stabilizing the cardiac responses to precipitous falls in blood pressure that occur in obstructure breathing.
AB - Cardiovascular control during asthma and other forms of obstructed breathing has not been extensively investigated. Previous studies in dogs have shown that obstructed breathing or an inspiratory effort against a blocked airway (Mueller maneuver) provoke large oscillations in blood pressure. During the inspiratory phase transmural systolic pressure relative to atmosphere drops initially, but transmural systolic pressure relative to intrathoracic pressure can remain unchanged or even increase. Because the carotid baroreceptors are located in the extrathoracic circulation, whereas the aortic baroreceptors are located in the intrathoracic circulation, and each responds to local transmural arterial pressure, simultaneous baroreceptor output from these 2 areas was measured in the anesthetized cat during normal and obstructed breathing and during Mueller maneuvers. Both whole-nerve and single-fiber preparations showed a significantly decreased output from the carotid baroreceptors during obstructed inspiratory efforts, whereas aortic baroreceptor output decreased significantly less or not at all. Transmural systolic pressure decreased significantly less in the aorta than in the carotid regions. Further, the aortic baroreceptors were more sensitive to changes in pulse pressure than were the carotid baroreceptors. These results suggest a mechanism for stabilizing the cardiac responses to precipitous falls in blood pressure that occur in obstructure breathing.
UR - http://www.scopus.com/inward/record.url?scp=0019572103&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0019572103&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.1981.240.5.h721
DO - 10.1152/ajpheart.1981.240.5.h721
M3 - Article
C2 - 7235031
AN - SCOPUS:0019572103
SN - 0363-6135
VL - 9
SP - H721-H729
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 5
ER -