AJP - Regulatory, Integrative and Comparative Physiology, Vol 247, Issue 1 34-R39, Copyright © 1984 by American Physiological Society
Effect of a purified atrial natriuretic factor on rat and rabbit vascular strips and vascular beds
R. Garcia, G. Thibault, M. Cantin and J. Genest
Rat atrium cardiocytes contain a powerful natriuretic and diuretic peptide
that has been localized in the specific granules. This atrial natriuretic
factor (ANF) produced a potent, dose-dependent relaxant effect on rabbit
and rat arterial strips previously made to contract by application of
either norepinephrine (NE) or angiotensin II. The effect was not seen if
KCl was used as contractile agent or under any conditions with rabbit
mesenteric strips. After the application of ANF the vascular strips were
refractory to subsequent stimulation by either NE or angiotensin II. The
infusion of ANF into a high-resistance isolated perfused rat kidney
produced a rapid decrease (33 +/- 5 mmHg) in perfusion pressure that lasted
for 18 +/- 3 min. This effect was not seen in the isolated rat mesenteric
arterial preparation, even when the perfusion pressure was raised by the
infusion of NE. These effects of ANF on vascular smooth muscle are not
mediated by prostaglandins, by alpha- and beta-adrenergic and muscarinic
receptors, or by an impairment of Ca2+ influx, but they are mimicked by
sodium nitroprusside. A low- and a high-molecular-weight ANF produced the
same effects. The existence of specific receptive sites for these peptides
is suggested.
