Hypertension, Vol 7, 216-222, Copyright © 1985 by American Heart Association
RW Lappe, KW Barron, JE Faber and MJ Brody
The effects of nisoldipine administration on vascular reactivity to humoral
and neural vasoconstrictor stimuli were examined in the intact rat. For
these experiments, rats were instrumented with miniaturized pulsed Doppler
flow probes to allow continuous measurement of renal, mesenteric, and
hindquarters blood flow. In conscious and anesthetized rats, intravenous
doses of angiotensin II (75 and 150 ng/kg), norepinephrine (0.6 and 1.2
microgram/kg), and epinephrine (0.6 and 1.2 microgram/kg) caused
dose-dependent increases in arterial pressure and renal and mesenteric
vascular resistance. Nisoldipine (0.7 microgram/min) administration
significantly attenuated (p less than 0.05) the pressor and regional
vasoconstrictor actions of all three circulating pressor agents; however,
nisoldipine infusion had little effect on neurally mediated regional
vasoconstrictor responses elicited by electrical stimulation of the
posterior hypothalamus or greater splanchnic nerve. These data indicate
that nisoldipine depressed vascular responsiveness to humoral
vasoconstrictor agents, while neural vasoconstrictor responses were
unaffected. Thus nisoldipine appears to exert preferential antagonistic
effects on humoral rather than on neural vasoconstrictor stimuli.
ARTICLES
Selective antagonism of humoral versus neural vasoconstrictor responses by nisoldipine
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