Journal of Applied Physiology, Vol 63, Issue 6 2476-2481, Copyright © 1987 by American Physiological Society
Effect of vagotomy and thoracic sympathectomy on responses of the monkey to water immersion
T. V. Peterson, B. A. Benjamin and N. L. Hurst
Department of Medical Physiology, Texas A&M University College of Medicine, College Station 77843.
Cardiopulmonary stretch receptors have been implicated as part of a reflex
mechanism linking changes in blood volume to changes in renal excretion.
Experiments were performed to determine whether total denervation of these
receptors by combined cervical vagotomy and thoracic sympathectomy affects
the renal responses of the monkey to head-out water immersion, a maneuver
that translocates blood to the thorax and elicits an increase in renal salt
and water excretion. Macaca fascicularis monkeys first underwent chronic
bilateral thoracic sympathectomy or sham denervation performed in two
stages a week apart. One to two weeks later, they were anesthetized with
pentobarbital sodium, and the sympathectomized animals underwent bilateral
cervical vagotomy. Control renal function did not differ between the two
groups. Immersion of 90-min duration increased central venous and mean
arterial pressures by similar amounts in both groups, but heart rate
increased only in the sham-denervated animals. Denervation did not affect
the magnitudes or delay the times of onset of the increases in urine flow,
absolute and fractional sodium excretion, and osmolar and free water
clearances occurring with immersion. These results demonstrate that in the
anesthetized monkey cardiopulmonary receptors are not necessary for
eliciting the renal responses to immersion.
