Somatosensory influences on renal sympathetic nerve activity in
anaesthetised wistar and hypertensive rats.
Zhang, Tao, and Edward J Johns.
Department of Physiology, The Medical School, Birmingham B15 2TT,
United Kingdom
APStracts 3:0426R, 1996.
This study compared the cardiovascular and renal nerve activity
responses to somatosensory stimulation with capsaicin in normotensive
and hypertensive rats. The importance of the cardiopulmonary
receptors in these two states was examined using phenylbiguanide
(PBG) infusion. Subcutaneous capsaicin increased blood pressure (BP),
heart rate (HR), renal nerve activity (RNA) 6-35% (P<0.01)
while total power, TP and % power at HR (%PHR) rose two-three fold
(P<0.001). PBG reduced basal RNA, TP and %PHR (20-70%,
P<0.05) did not change the cardiovascular but attenuated the
TP and %PHR increases due to capsaicin (P<0.001-0.01). PBG
given to vagotomised normotensive rats, normalised the cardiovascular
and RNA responses to capsaicin. In hypertensive rats, capsaicin
increased BP, HR, RNA (10-20%), TP and %PHR (50-70%, P<0.001).
PBG infusion into hypertensive rats decreased RNA (20%,
P<0.01), while the capsaicin-dependent rise in RNA was smaller
(P<0.05) those of TP and %PHR were unchanged but in
vagotomised hypertensive rats given PBG, these responses were
minimally affected. Somatosensory modulation of RNA power spectra was
suppressed by the cardiopulmonary receptors in normotensive rats, but
in hypertensive rats their impact was much smaller.
Received 12 March 1996; accepted in final form 26 September 1996.
APS Manuscript Number R153-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996