AJP - Heart and Circulatory Physiology, Vol 257, Issue 4 1104-H1109, Copyright © 1989 by American Physiological Society
Effects of antiserum against alpha-rat atrial natriuretic polypeptide in spontaneously hypertensive rats
A. Sasaki, O. Kida, T. Kita, J. Kato, S. Nakamura, K. Kodama, A. Miyata, K. Kangawa, H. Matsuo and K. Tanaka
First Department of Internal Medicine, Miyazaki Medical College, Japan.
To clarify the physiological role of endogenous atrial natriuretic
polypeptide (ANP), we investigated the effects of specific rabbit antiserum
against alpha-rat ANP (alpha-rANP) on hemodynamics, diuresis, and
natriuresis in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats
(WKY). Intravenous administration of anti-alpha-rANP antiserum caused an
obvious rise of mean blood pressure and cardiac output in both SHR and WKY
compared with rats administered with normal rabbit serum. Although there
was no significant difference in increments of mean blood pressure between
SHR and WKY, the increment of cardiac output in SHR was significantly
higher than that in WKY. On the other hand, significant reductions in urine
output and urinary sodium and potassium excretion lasted for approximately
20 min after administration of the antiserum in both SHR and WKY compared
with rats administered with normal rabbit serum. There was no significant
difference in these initial maximal decrements between SHR and WKY. These
results indicate that endogenous ANP has an important physiological role in
the regulation of hemodynamics and water-electrolyte balance in both SHR
and WKY. The greater increment of cardiac output in SHR in response to the
antiserum suggests that endogenous ANP in SHR may have a stronger
cardiosuppressive action that it does in WKY.
