AJP - Heart and Circulatory Physiology, Vol 253, Issue 5 1136-H1140, Copyright © 1987 by American Physiological Society
alpha-ANP alters reflex control of lumbar and renal sympathetic nerve activity and heart rate
T. Imaizumi, A. Takeshita, H. Higashi and M. Nakamura
Research Institute of Angiocardiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
This study examined the effects of synthetic alpha-rat atrial natriuretic
peptide (alpha-rANP) on arterial pressure (AP), heart rate (HR), and renal
and lumbar sympathetic nerve activity (SNA) in rats with intact arterial
baroreceptors before and after bilateral vagotomy and in those with
sinoaortic denervation before and after vagotomy. In intact rats,
alpha-rANP decreased AP, which was accompanied by the decrease in renal SNA
ad HR and no change in lumbar SNA. In contrast, the increase in lumbar SNA
and HR occurred during hypotension caused by nitroglycerin. In rats with
intact arterial baroreceptors and vagi sectioned, renal and lumbar SNA and
HR did not change during hypotension with alpha-rANP. In addition,
alpha-rANP did not alter the gain of arterial baroreflex control of lumbar
SNA in these rats. In rats with sinoaortic denervation, alpha-rANP
decreased HR and renal and lumbar SNA before vagotomy but did not change
them after vagotomy. These results suggest, first, that alpha-rANP
activates vagal afferents and thereby inhibits renal and lumbar SNA and HR
and, second, that alpha-rANP may reset arterial baroreflex control of SNA
and HR to a lower pressure range.
