Hypertension, Vol 7, 39-46, Copyright © 1985 by American Heart Association
WD Sweet, RH Freeman, JO Davis and D Villarreal
The acute response to ganglionic blockade (hexamethonium bromide, 30 mg/kg,
i.v.) was used to evaluate the neurogenic contributions to mean arterial
pressure maintenance in the conscious one-kidney, one clip hypertensive
dog. Approximately 2 hours (112 minutes) after ganglionic blockade,
captopril (10 mg/kg, i.v.) was given to block the renin- angiotensin
system. Hypertensive animals were studied 3 days after clipping (group 2)
or 2 to 4 weeks after clipping (groups 3 and 4). Groups 2 and 3 were fed a
regular sodium diet, but group 4 animals were sodium and volume depleted.
Normotensive control animals (group 1) were fed a regular sodium diet. On
the day of the acute experiment the baseline blood pressures measured in
group 2 (151 +/- 10 mm Hg, n = 5), group 3 (154 +/- 5 mm Hg, n = 7), and
group 4 (160 +/- 8 mm Hg, n = 7) were not different (p greater than 0.05)
from each other, but all were elevated (p less than 0.05) compared with the
group 1 animals (106 +/- 3 mm Hg, n = 8). Also, there were no significant
differences (p greater than 0.05) in the baseline plasma catecholamine
levels among the three hypertensive groups. Ganglionic blockade produced a
greater fall in blood pressure (p less than 0.05) in the
sodium/volume-depleted dogs of group 4 (-35 mm Hg) than in group 1 (-10 mm
Hg), group 2 (-3 mm Hg), or group 3 (-12 mm Hg) animals.(ABSTRACT TRUNCATED
AT 250 WORDS)
ARTICLES
Sodium and volume depletion activates neurogenic mechanisms in renal hypertensive dogs