|
|
||||||||
Dogs were anaesthetized with chloralose, the regions of both carotid sinuses were vascularly isolated and perfused with arterial blood and both cervical vagosympathetic trunks were cut above the nodose ganglia. The cephalic circulation was perfused through the brachiocephalic and left subclavian arteries with blood which was equilibrated with various levels of CO2. The abdomen was vascularly isolated, perfused through the aorta at constant flow and drained through the inferior vena cava at constant pressure. Changes in vascular resistance were determined from changes in abdominal aortic perfusion pressure and changes in capacitance from the integral of the changes in venous outflow. An increase in PCO2 in the cephalic perfusate resulted in an increase in abdominal vascular resistance and a decrease in capacitance. However, when carotid sinus pressure was high, the response of resistance to an increase in cephalic PCO2 was abolished and that of capacitance was significantly reduced. The reflex responses of both vascular resistance and capacitance to a change in carotid sinus pressure were enhanced when the cephalic PCO2 was raised. However, the effect on the reflex capacitance response from stimulation of baroreceptors was obtained only when PCO2 was changed below 5 kPa whereas the effect on resistance occurred at higher values of PCO2. The interaction between the effects of changes in cephalic PCO2 and the carotid sinus reflex and the differential effect on resistance and capacitance vessels have been explained in terms of the known difference in the sensitivities of these vessels to sympathetic nerve activity.
This article has been cited by other articles:
![]() |
V. L Cooper, S. B Pearson, C. M Bowker, M. W Elliott, and R Hainsworth Interaction of chemoreceptor and baroreceptor reflexes by hypoxia and hypercapnia - a mechanism for promoting hypertension in obstructive sleep apnoea J. Physiol., October 15, 2005; 568(2): 677 - 687. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. K. Shoemaker, D. D. O'Leary, and R. L. Hughson PETCO2 inversely affects MSNA response to orthostatic stress Am J Physiol Heart Circ Physiol, September 1, 2001; 281(3): H1040 - H1046. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Tominaga, T. A. Stekiel, Z. J. Bosnjak, and J. P. Kampine Contribution of carotid chemoreceptors to mesenteric venoconstriction during acute hypercapnia in rabbits Am J Physiol Heart Circ Physiol, December 1, 1999; 277(6): H2305 - H2310. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. N. Browning, Z. Zheng, D. L. Kreulen, and R. A. Travagli Two populations of sympathetic neurons project selectively to mesenteric artery or vein Am J Physiol Heart Circ Physiol, April 1, 1999; 276(4): H1263 - H1272. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |