MINIREVIEW
Nitric Oxide-Compromised Hypertension: Facts and Enigmas
M. GEROVÁ
Institute of Normal and Pathological Physiology, Slovak
Academy of Sciences, Bratislava, Slovak Republic
Received July
30, 1999
Accepted September 21, 1999
Summary
NO concentration in the femoral artery and femoral vein of
anesthetized dogs was found to be 154.2± 5.6 nM and 90.0± 12 nM,
respectively. Inhibition of NO synthase (NOS) slightly decreased
the basal NO concentration in femoral artery from 154.2± 5.6 to
137.2± 3.3 nM. Acetylcholine-induced increase in NO
concentration was slightly but still significantly attenuated,
suggesting that very probably L-NAME did not inhibit all sources
of nitric oxide (NO). Local NOS inhibition in the posterior
hypothalamus dose-dependently increased systemic blood pressure
(BP) in rats. Short-term general NOS inhibition in anesthetized
dogs increased diastolic BP but not systolic BP. The heart rate
after one-hour down-fluctuation returned to initial values.
Proteosynthesis in the myocardium and both branches of the left
coronary artery increased, but this was not supported by
polyamines, since the activity of ornithine decarboxylase
declined. Long-term general NOS inhibition elicited a sustained
BP increase, a decrease in heart rate, cardiac hypertrophy and
an increase in wall thickness of the coronary and carotid
artery. The results indicate that NO deficiency itself plays a
role in proteosynthesis and cardiac hypertrophy, in spite of
relatively small increase in diastolic blood pressure and no
change in systolic blood pressure, at least after an acute
L-NAME administration. The hypotension response to acetylcholine
and bradykinin studied in anesthetized NO-compromised rats, was
unexpectedly enhanced. The elucidation of this paradoxical
phenomenon will require further experiments.
Key
words
NO level in vivo · Hypothalamus · Hypertension · L-NAME acute administration · L-NAME
chronic administration · Polyamines
Reprint
requests
M. Gerová, MD, DSc, Institute of Normal and Pathological Physiology, Slovak Academy of
Sciences,
Sienkewiczova 1, 813 71 Bratislava, Slovak Republic, Fax +421-7-368 516, e-mail: gerova@unpf.savba.sk.
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