This study examines the effects of female sex hormones on the vasoconstrictor response to electrical field stimulation (EFS), as well as the modulation of this response by neuronal NO. For this purpose, segments of denuded superior mesenteric artery from ovariectomized (OvX) female Sprague–Dawley rats and from control rats (in oestrus phase) were used. EFS induced frequency-dependent contractions, which were greater in segments from OvX rats than in those from control rats. The NO synthase inhibitor NG-nitro-l-arginine methyl ester strengthened EFS-elicited contractions to a greater extent in arteries from OvX rats than in those from control rats. Similar results were observed with the preferential neuronal NO synthase inhibitor 7-nitroindazole. The sensorial neurotoxin capsaicin did not modify EFS-induced contractions in segments from either group. In noradrenaline-precontracted segments, sodium nitroprusside (SNP) induced concentration-dependent relaxation, which was greater in segments from control rats than in those from OvX rats. 8-Bromo-cGMP induced similar concentration-dependent relaxation in noradrenaline-precontracted segments from both OvX and control rats. Diethyldithiocarbamate, a superoxide dismutase (SOD) inhibitor, reduced the relaxation induced by SNP in segments from both groups of rats. SOD, a superoxide anion scavenger, enhanced the relaxation induced by SNP in segments from OvX rats, but did not modify it in segments from control rats. EFS induced NO−2 formation, which was greater in segments from OvX than in those from control rats, and pretreatment with tetrodotoxin, a blocker of nerve impulse propagation, abolished release in both cases. These results suggest that EFS induces greater neuronal NO release in mesenteric segments from OvX rats than in those from control rats and, although NO metabolism is also higher, the contribution of net neuronal NO in the vasomotor response to EFS is greater in segments from OvX rats than in those from control rats.
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Research Article|
August 07 2002
Role of female sex hormones in neuronal nitric oxide release and metabolism in rat mesenteric arteries
Nuria MINOVES;
Nuria MINOVES
1Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, c/Arzobispo Morcillo 4, 28029-Madrid, Spain
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Gloria BALFAGÓN;
Gloria BALFAGÓN
1Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, c/Arzobispo Morcillo 4, 28029-Madrid, Spain
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Mercedes FERRER
1Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, c/Arzobispo Morcillo 4, 28029-Madrid, Spain
Correspondence: Dr Mercedes Ferrer (e-mail [email protected]).
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Publisher: Portland Press Ltd
Received:
November 08 2001
Revision Received:
February 04 2002
Accepted:
May 21 2002
Online ISSN: 1470-8736
Print ISSN: 0143-5221
The Biochemical Society and the Medical Research Society © 2002
2002
Clin Sci (Lond) (2002) 103 (3): 239–247.
Article history
Received:
November 08 2001
Revision Received:
February 04 2002
Accepted:
May 21 2002
Citation
Nuria MINOVES, Gloria BALFAGÓN, Mercedes FERRER; Role of female sex hormones in neuronal nitric oxide release and metabolism in rat mesenteric arteries. Clin Sci (Lond) 1 September 2002; 103 (3): 239–247. doi: https://doi.org/10.1042/cs1030239
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