Journal of Applied Physiology, Vol 65, Issue 1 109-115, Copyright © 1988 by American Physiological Society
Reflex mechanisms for changes in renal nerve activity during positive end-expiratory pressure
M. Aibiki, S. Koyama, K. Ogli and Y. Shirakawa
Department of Physiology, Shinshu University School of Medicine, Nagano, Japan.
This study was designed to investigate the interaction between carotid
sinus baroreceptors and cardiopulmonary receptors in the reflex control of
renal nerve activity (RNA) during positive end-expiratory pressure (PEEP)
in anesthetized dogs. PEEP at two different levels (10 and 20 cmH2O) was
applied to the following groups: animals with neuraxis intact (I group, n =
12); vagal and aortic nerve denervated animals with carotid sinus nerves
intact (V group, n = 6); carotid sinus denervated animals with vagal and
aortic nerves intact (SD group, n = 6); and carotid sinus denervated
animals also having severed vagal and aortic nerves (SAV group, n = 12).
Mean blood pressure (MBP), central venous pressure, and mean airway
pressure were also simultaneously measured. In the I group, no significant
alterations in RNA occurred during PEEP at both levels, even when MBP fell
significantly. Although the drop in MBP in the SD group was similar to that
in the I group, RNA decreased significantly 10 s after intervention at both
PEEP levels, followed by a recovery of RNA toward the control level. In
contrast, a significant increase in RNA, which continued until the end of
PEEP, appeared in the V group immediately after each intervention. In the
SAV group, RNA responses to PEEP, which were observed in the other groups,
were abolished. These results provide evidence that during PEEP, renal
nerve activity is modified by an interaction between carotid sinus
baroreceptors and cardiopulmonary receptors; excitatory effects occur via
carotid sinus nerves and inhibitory effects occur via vagal afferents.
