AJP - Heart and Circulatory Physiology, Vol 241, Issue 2 268-H272, Copyright © 1981 by American Physiological Society
Continuous blood pressure measurement in rats with aortic baroreceptor deafferentation
G. D. Fink, W. J. Bryan, M. Mann, J. Osborn and A. Werber
The purpose of this study was to determine if once-daily arterial pressure
measurements are a reliable estimate of actual time-averaged arterial
pressure in neurogenic hypertensive rats. Male rats were subjected to
either aortic baroreceptor deafferentation (ABD, n = 10) or sham operation
(SO, n = 10). One to 3 mo later, arterial pressure (AP) was recorded from a
chronic indwelling catheter in each rat for 72 continuous hours.
Subsequently, AP was determined once a day (10- to 30-min recording
periods) in each rat for an additional 3 consecutive days. Continuous
recording yielded an average mean arterial pressure (MAP) of 104 +/- 2 mmHg
in SO rats and an average mean MAP of 120 +/- 3 mmHg in ABD rats. Standard
deviation of MAP measured every 5 min for 24 consecutive hours (as an index
of pressure lability) was 8.0 +/- 0.4 mmHg in SO rats and 14.4 +/- 1.3 mmHg
in ABD rats. Both of the above differences were statistically significant
(P less than 0.05). The average MAP from daily measurements in the same
rats was 107 +/- 3 mmHg in SO rats and 124 +/- 3 mmHg in ABD rats. Average
pressure values were not statistically different for the two measurement
techniques in either group of rats. Overall, there existed a significant
correlation (r = 0.64, P less than 0.01) between MAP measured continuously
and daily in the 20 rats studied. We conclude that daily direct measurement
of MAP in conscious ABD rats yields a satisfactory estimate of actual
time-averaged MAP in these rats despite their markedly increased MAP
lability.
