Aging is not accompanied by sympathetic hyperresponsiveness to air
-jet stress.
Stauss, Harald M., Donald A. Morgan, Karl E. Anderson, Michael P.
Massett, and Kevin C. Kregel.
Department of Exercise Science, The University of Iowa, Iowa City,
Iowa 52242
APStracts 3:0001H, 1996.
It has been postulated that sympathetic nervous system reactivity to
acutely applied stress is increased with age. Therefore, we
investigated the autonomic and hemodynamic adjustments to air jet
stress in nine mature (12-month-old) and eleven senescent (24-month
-old) Fischer 344 rats. Rats were instrumented with arterial and
venous catheters, flow probes around the renal artery and nerve
electrodes on the ipsilateral renal nerve. After recovery from
surgery, blood pressure, heart rate, renal blood flow, and renal
sympathetic nerve activity were recorded during control conditions
and an eight minute continuous air jet application. Renal resistance
and the low (0.01 - 0.20 Hz) and mid frequency (0.20 - 0.50 Hz) power
of blood pressure were computed off-line. Air jet induced an increase
in blood pressure, heart rate, renal resistance, renal nerve
activity, and blood pressure power in the low and mid frequency
ranges in both groups. Blood pressure and low frequency blood
pressure power increased less, and the elevations in renal resistance
and renal nerve activity were of shorter duration in senescent
compared with mature rats. These data suggest that sympathetic
responsiveness to air jet stress is not enhanced with increasing age.
Received 25 October 1995; accepted in final form 7 December 1995.
APS Manuscript Number H1000-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 22 January 96