Reflex effects on components of synchronized renal sympathetic
nerve activity.
Dibona, Gerald F., and Susan Y. Jones.
Department of Internal Medicine University of Iowa College of
Medicine and Veterans Administration Medical Center, Iowa City, IA
52242
APStracts 5:0110F, 1998.
The effects of peripheral thermal receptor stimulation (tail in hot
water, N=8, anesthetized) and cardiac baroreceptor stimulation
(volume loading, N=8, conscious) on components of synchronized renal
sympathetic nerve activity were examined in rats. The peak height and
peak frequency of synchronized renal sympathetic nerve activity were
determined. The renal sympathoexcitatory response to peripheral
thermal receptor stimulation was associated with an increase in the
peak height. The renal sympathoinhibitory response to cardiac
baroreceptor stimulation was associated with a decrease in the peak
height. Although heart rate was significantly increased with
peripheral thermal receptor stimulation and significantly decreased
with cardiac baroreceptor stimulation, peak frequency was unchanged.
As peak height reflects the number of active fibers, reflex increases
and decreases in synchronized renal sympathetic nerve activity are
mediated by parallel increases and decreases in the number of active
renal nerve fibers rather than changes in the centrally based rhythm
or peak frequency. The increase in the number of active renal nerve
fibers produced by peripheral thermal receptor stimulation reflects
the engagement of a unique group of silent renal sympathetic nerve
fibers with a characteristic response pattern to stimulation of
arterial baroreceptors, peripheral and central chemoreceptors and
peripheral thermal receptors.
Received 22 October 1997; accepted in final form 11 June 1998.
APS Manuscript Number F339-7.
Article publication pending Am. J. Physiol. (Renal Physiology).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 30 July 1998