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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

SYNAPTIC PROFILE OF NUCLEUS TRACTUS SOLITARIUS NEURONS INVOLVED WITH THE PERIPHERAL CHEMOREFLEX PATHWAYS

Texto completo
Autor(es):
Accorsi-Mendoca, D. [1] ; Castania, J. A. [1] ; Bonagamba, L. G. H. [1] ; Machado, B. H. [1] ; Leao, R. M. [1]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Physiol, BR-14049900 Sao Paulo - Brazil
Número total de Afiliações: 1
Tipo de documento: Artigo Científico
Fonte: Neuroscience; v. 197, p. 107-120, DEC 1 2011.
Citações Web of Science: 21
Resumo

The glomus cells in the carotid bodies (CB) detect alterations in pH and pCO(2) and low pO(2) level in arterial blood. The carotid sinus nerve conveys the information related to the oxygen level to 2nd-order neurons in the nucleus tractus solitarius (NTS) via tractus solitarius (TS), which is part of the chemoreflex pathways. It has been demonstrated that in 2nd-order NTS neurons receiving inputs from the aortic depressor nerve (ADN), the TS stimulation presents high temporal fidelity. However, the temporal properties of synaptic activity in NTS neurons receiving inputs from CB were not yet fully investigated. Herein using patch-clamp recordings in NTS brainstem slices, we studied TS-evoked excitatory postsynaptic currents (TS-eEPSCs) on morphologically identified 2nd-order NTS neurons that receive afferent inputs from the CB and compared with 2nd-order ADN-NTS neurons recorded in the same experimental conditions. The amplitudes of TS-eEPSCs were similar in both groups, but the latencies and standard deviation (SD) of latency were significantly higher in the CB-NTS neurons (latency: 4 +/- 0.2 ms, SD: 0.49 +/- 0.03 ms) than in ADN-NTS neurons (latency: 3.3 +/- 0.3 ms, SD: 0.19 +/- 0.02 ms; P=0.049 for latency and P<0.001 for SD of latency). In a series of double-labeling experiments, we confirmed that some CB-NTS 2nd-order neurons send direct projections to the rostral ventrolateral medulla (RVLM). We conclude that: (a) CB-NTS 2nd-order neurons present temporally distinct postsynaptic currents when compared with ADN-NTS 2nd-order neurons; (b) low SD of latency of TS-eEPSCs is not necessarily a characteristic of all 2nd-order neurons in the NTS; and (c) the presence of direct connections between these 2nd-order neurons in the NTS and RVLM is indicative that these synaptic properties of CB-NTS neurons are relevant for the processing of respiratory and autonomic responses to chemoreflex activation. (C) 2011 IBRO. Published by Elsevier Ltd. All rights reserved. (AU)

Processo FAPESP: 03/05016-0 - Caracterização eletrofisiológica dos neurônios do núcleo do trato solitário envolvidos com a modulação da atividade simpática: participação dos receptores de aminoácidos excitatórios e purinérgicos
Beneficiário:Daniela Accorsi Mendonça Eichenberger
Linha de fomento: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 03/04319-0 - Fisiologia e plasticidade da neurotransmissão em um núcleo envolvido no processamento e aprendizado auditivo
Beneficiário:Ricardo Mauricio Xavier Leão
Linha de fomento: Auxílio à Pesquisa - Regular
Processo FAPESP: 04/03285-7 - Mecanismos centrais da excitação simpática promovida pela hipóxia
Beneficiário:Benedito Honorio Machado
Linha de fomento: Auxílio à Pesquisa - Temático