Hypertension, Vol 2, 311-318, Copyright © 1980 by American Heart Association
RD Bunag, K Takeda and E Riley
Hypertension was induced experimentally by subjecting rats to vigorous
shaking, 4 hours (at random) daily for 14 weeks. Systolic pressures
measured with the tail-cuff method began to rise after the first week and
were significantly elevated on Weeks 3, 4, 6, 7, and 8, but reverted to
normotensive levels thereafter despite continued shaking. A similar
hypertension was then induced in another group of rats and when spontaneous
remission occurred, pressor responsiveness was tested on the eleventh week
by recording aortic pressures from indwelling catheters. Pressor responses
to further shaking or electrical stimulation of the anterior hypothalamus
were smaller in shaker- stressed than in control rats, while those to
injected norepinephrine were almost the same in both groups. Spike
potentials recorded from postganglionic sympathetic (splanchnic) nerves
showed higher baselines but smaller increases in neural firing during
hypothalamic stimulation in shaker-stressed than in control rats. These
results suggest that while shaker stress alone can induce hypertension, the
resulting blood pressure elevation is not sustained, perhaps because
adaptation within the central nervous system concurrently reduces pressor
responsiveness.
ARTICLES
Spontaneous remission of hypertension in awake rats chronically exposed to shaker stress
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