AJP - Regulatory, Integrative and Comparative Physiology, Vol 253, Issue 4 568-R575, Copyright © 1987 by American Physiological Society
Partition of carotid baroreceptor response in two-kidney renal hypertensive dogs
E. Koushanpour and R. Behnia
Department of Physiology, Northwestern University Medical School, Chicago, Illinois 60611.
This study evaluated the mechanism of carotid sinus baroreceptor resetting
in two-kidney one-clip Goldblatt hypertension in dogs by partitioning the
resetting between carotid sinus wall compliance and receptor neural
elements. With dogs under halothane anesthesia, the left renal artery was
constricted 70-80% with a Goldblatt clamp without disturbing the
contralateral kidney. Ten weeks later, when mean blood pressure had risen
to 151 +/- 6 mmHg (means +/- SE) compared with 105 +/- 5 mmHg in controls,
we measured simultaneously whole nerve action potentials (N) and carotid
sinus volume (V) during step changes in intrasinus pressure (P).
Hypertensive N vs. P relationship was sigmoid shaped and shifted toward the
P-axis compared with controls. Hypertensive V vs. P relationship was not
significantly different from controls. The hypertensive N vs. V
relationship derived from the composite plots of N vs. P and V vs. P was
sigmoid shaped and shifted toward the V-axis compared with controls. These
results suggest that the resetting of baroreceptors is due to changes in
receptor properties rather than carotid sinus wall compliance.
