Wd. Franke et Nb. Tegeler, EFFECTS OF ALPHA(1)-BLOCKADE ON MAXIMAL VASCULAR CONDUCTANCE IN YOUNGBORDERLINE HYPERTENSIVES, Clinical and experimental hypertension, 19(8), 1997, pp. 1219-1232
This study was conducted to determine if reducing sympathetic tone wit
h alpha(1)-adrenergic receptor blockade affected the maximal forearm v
ascular conductance (FVCmax; reactive hyperemia) responses in young bo
rderline hypertensives and normotensive controls. The FVC response fol
lowing ischemia (14 min arterial occlusion with 3 min of hand exercise
) was determined after systemic alpha(1)-blockade (5 mg prazosin in pr
eceding 24 h) in hypertensives (n=11, MAP=110+/-1, age=24.5+/-1.1, (x)
over bar+/-SEM) and normotensives (n=13, MAP=82+/-1, age=22.5+/-0.3).
During the placebo trial, resting FVC was lower in the hypertensives
than the normotensives (.0472+/-.0073 vs. 0755+/-.0095 units; P<.05).
During alpha(1)-blockade, FVC did not differ between the groups. Withi
n each group, FVCmax did not differ significantly between either trial
. During placebo, FVCmax was lower (P<.05) in the hypertensives (.3485
+/-.0335 vs. 5641+/-.0503 units) and remained so during alpha(1)-block
ade (.4048+/-.0520 vs .5286+/-.0275 units; P<.05). These data suggest
that alpha(1)-blockade does not increase FVCmax in borderline hyperten
sives and that both functional and structural changes in the periphera
l vasculature are involved in the blood pressure elevations seen in th
is group.