Jl. Delgado et al., EFFECT OF N-ACETYLCYSTEINE ON VASCULAR ENDOTHELIUM FUNCTION IN AORTA FROM OOPHORECTOMIZED RATS, General pharmacology, 32(1), 1999, pp. 23-27
1. Experiments were performed to examine and to compare vascular endot
helial function in aortic rings from oophorectomized and from ovary-in
tact rats and to test the effect of thiol compound as N-acetylcysteine
on endothelial function. 2. In precontracted aortic rings from oophor
ectomized and intact rats, vascular endothelial function was evaluated
by measuring changes in isometric force in response to cumulative dos
es of superoxide dismutase, acetylcholine and sodium nitroprusside. 3.
In studies designed to assess the tone-related release of nitric oxid
e from aortic rings moderately precontracted with phenylephrine, super
oxide dismutase produced a lower concentration-related relaxant respon
se in aortic rings from oophorectomized rats than from ovary intact ra
ts. 4. Acetylcholine caused a concentration- and endothelium-dependent
relaxation of less magnitude in aortic rings from oophorectomized ani
mals compared with those from ovary-intact rats. Addition of N-omega-n
itro-L-arginine methyl ester eliminated the relaxation induced by both
superoxide dismutase and acetylcholine. 5. No differences between gro
ups were noticed in the concentration-relaxation curve induced by sodi
um nitroprusside. 6. Preincubation with N-acetylcysteine normalized th
e depressed vasorelaxant response to acetylcholine in the aortic rings
from oophorectomized rats, whereas the concentration-response curve f
or acetylcholine in aortic rings from ovary-intact rats did not alter.
7. These results suggest that the absence of ovary estrogens is assoc
iated with a vascular endothelium dysfunction that can be reverted by
addition of N-acetylcysteine, a thiol-containing compound with a free
radical scavenger effect. (C) 1998 Elsevier Science Inc.