AJP - Regulatory, Integrative and Comparative Physiology, Vol 258, Issue 3 616-R623, Copyright © 1990 by American Physiological Society
Pentobarbital anesthesia alters renal actions of alpha-hANP in dogs
J. B. Madwed and B. C. Wang
St. Luke's Hospital and Foundation, Kansas City, Missouri 64111.
The magnitude of the natriuretic response to an infusion of alpha-human
atrial natriuretic peptide (alpha-hANP) has varied considerably in
different studies. The greatest renal responses to alpha-hANP infusion have
been observed in barbiturate-anesthetized dogs. We therefore examined the
renal, hormonal, and cardiovascular responses to alpha-hANP infusion in
eight female dogs, once awake and again anesthetized with pentobarbital
sodium (25 mg/kg body wt). After a 20-min control period, alpha-hANP was
infused at a rate of 25 ng.kg-1.min-1 for 60 min. In dogs when awake,
infusion of alpha-hANP produced a significant increase in sodium excretion
from a control value of 39 +/- 7 to 73 +/- 13 and 89 +/- 15 mu eq/min after
40 and 60 min. In dogs when anesthetized, infusion of alpha-hANP produced
an increase in sodium excretion from 21 +/- 3 to 105 +/- 12 and 143 +/- 21
mu eq/min after 40 and 60 min. The increase in sodium excretion was
significantly greater in dogs when anesthetized than when awake. We also
investigated the role of the renal sympathetic nerves on these responses in
six dogs after chronic bilateral renal denervation. In dogs with denervated
kidneys when awake, infusion of alpha-hANP did not change sodium excretion
significantly. In dogs with denervated kidneys when anesthetized, infusion
of alpha-hANP significantly increased sodium excretion; however, the
increase was significantly attenuated when compared with anesthetized dogs
with intact kidneys. We conclude that the natriuretic response to an
infusion of alpha-hANP is enhanced in dogs when anesthetized. Also, the
natriuretic response was attenuated by renal denervation in dogs when
anesthetized.
