Central nitric oxide donors attenuate cardiovascular and central
norepinephrine responses to stress.
Hashiguchi, Hiro, Shao H. Ye, Fred Ross-Cisneros, and Natalie
Alexander.
University of Southern California School of Medicine, Dept. of
Medicine and Miyazaki Medical College, Dept. of Psychiatry
APStracts 3:0393R, 1996.
An earlier study showed that norepinephrine(NE) was released in the
paraventricular nucleus(PVN) and posterior hypothalamus(PH) along
with increases of mean arterial pressure(MAP) and heart rate(HR)
during shaker stress(SS). Here we investigated the possibility that
nitric oxide(NO) donors, infused into hypothalamus, could modulate
responses to SS. In conscious rats, an injector- microdialysis probe,
for direct application of donor and collection of extracellular NE,
respectively, was inserted into PVN or PH; MAP and HR were recorded
continuously from conscious rats. The NO donor, molsidomine(MOL),
infused 5 or 30 min prior to SS, did not alter baseline values of NE,
MAP or HR but did attenuate changes elicited by 5 min of SS;
methylene blue blocked the effects of MOL. The NO donor, sodium
nitroprusside, was much less effective than MOL as a modulator of
stress related effects. The results indicate that MAP, HR and
hypothalamic NE responses to environmental stress, but not baseline
values, can be modulated by NO donors in the hypothalamus.
Received 12 March 1996; accepted in final form 14 October 1996.
APS Manuscript Number R149-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996