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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Fluorescent indication that nitric oxide formation in NTS neurons is modulated by glutamate and GABA

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Author(s):
Pajolla, Gisela P. [1] ; Accorsi-Mendonca, Daniela [1] ; Rodrigues, Gerson J. [2] ; Bendhack, Lusiane M. [2] ; Machado, Benedito H. [1] ; Lunardi, Claure N. [3]
Total Authors: 6
Affiliation:
[1] Univ Sao Paulo, Sch Med, Dept Physiol, BR-14049900 Ribeirao Preto, SP - Brazil
[2] Univ Sao Paulo, Sch Pharmaceut Sci, Dept Chem & Phys, BR-14049900 Ribeirao Preto, SP - Brazil
[3] Univ Brasilia, Coll Ceilandia, BR-70910900 Brasilia, DF - Brazil
Total Affiliations: 3
Document type: Journal article
Source: NITRIC OXIDE-BIOLOGY AND CHEMISTRY; v. 20, n. 3, p. 207-216, APR 15 2009.
Web of Science Citations: 9
Abstract

Nitric oxide (NO) in NTS plays an important role in regulating autonomic function to the cardiovascular system. Using the fluorescent dye DAF-2 DA, we evaluated the NO concentration in NTS. Brainstem slices of rats were loaded with DAF-2 DA, washed, fixed in paraformaldehyde and examined under fluorescent light. In different experimental groups, NTS slices were pre-incubated with 1 mM L-NAME (a non-selective NOS inhibitor), 1 MM D-NAME (an inactive enantiomere of L-NAME), 1 mM kynurenic acid (a nonselective ionotropic receptors antagonist) or 20 mu M bicuculline (a selective GABA(A) receptors antagonist) before and during DAF-2 DA loading. Images were acquired using a confocal microscope and the intensity of fluorescence was quantified in three antero-posterior NTS regions. In addition, slices previously loaded with DAF-2 DA were incubated with NeuN or GFAP antibody. A semi-quantitative analysis of the fluorescence intensity showed that the basal NO concentration was similar in all antero-posterior aspects of the NTS (rostral intermediate, 15.5 +/- 0.8 AU: caudal intermediate, 13.2 +/- 1.4 AU; caudal commissural, 13.8 +/- 1.4 AU, n = 10). In addition, the inhibition of NOS and the antagonism of glutamatergic receptors decreased the NO fluorescence in the NTS. On the other hand, D-NAME did not affect the NO fluorescence and the antagonism of GABAA receptors increased the NO fluorescence in the NTS. It is important to note that the fluorescence for NO was detected mainly in neurons. These data show that the fluorescence observed after NTS loading with DAF-2 DA is a result of NO present in the NTS and support the concept that NTS neurons have basal NO production which is modulated by L-glutamate and GABA. (C) 2009 Elsevier Inc. All rights reserved. (AU)

FAPESP's process: 04/03285-7 - Central mechanisms involved in the sympathoexcitation in response to hypoxia
Grantee:Benedito Honorio Machado
Support type: Research Projects - Thematic Grants