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

Autor(es)

Pajolla, Gisela P. ^[1] ; Accorsi-Mendonca, Daniela ^[1] ; Rodrigues, Gerson J. ^[2] ; Bendhack, Lusiane M. ^[2] ; Machado, Benedito H. ^[1] ; Lunardi, Claure N. ^[3]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: NITRIC OXIDE-BIOLOGY AND CHEMISTRY; v. 20, n. 3, p. 207-216, APR 15 2009.
• Citações Web of Science: 9

Resumo

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)

• Processo FAPESP: 04/08868-0 - Consolidação do Centro de Microscopia Funcional do Campus da USP/ Ribeirão Preto
• Beneficiário: Roy Edward Larson
• Modalidade de apoio: Auxílio à Pesquisa - Programa Equipamentos Multiusuários
• Processo FAPESP: 04/03285-7 - Mecanismos centrais da excitação simpática promovida pela hipóxia
• Beneficiário: Benedito Honorio Machado
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 04/08712-0 - Imunorreatividade aos receptores de aminoacidos excitatorios e purinergicos no nucleo do trato solitario (nts) de ratos submetidos a hipoxia cronica intermitente.
• Beneficiário: Gisela Pugliesi Pajolla
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado