Sustained Hypoxia Reduces GABAergic Modulation on NTS Neurons Sending Projections to Ventral Medulla of Rats (Retracted article. See vol. 493, pg. 120, 2022)

Autor(es)

Pascoaloti-Lima, Julio C. ; Machado, Benedito H. ; Accorsi-Mendonca, Daniela

• Tipo de documento: Artigo Científico
• Fonte: Neuroscience; v. 457, p. 11-pg., 2021-01-28.

Resumo

Peripheral chemoreflex is activated during short-term sustained hypoxia (SH), and the first synapse of these afferents is located in Nucleus Tractus Solitarius (NTS). NTS neurons projecting to the ventral lateral medulla (NTS-VLM) are part of the respiratory pathways of the chemoreflex. SH increases the magnitude of basal respiratory parameters in rats from Wistar-Hannover strain. In this study, we hypothesized that the observed changes in the respiratory pattern in response to SH were due to changes in the GABAergic modulation of the synaptic transmission of NTS-VLM neurons. We used an electrophysiological approach to record the synaptic activity of NTS neurons labeled with a retrograde tracer previously microinjected into VLM of Wistar-Hannover rats submitted to 24 h SH. The data are showing that: (a) the amplitude of evoked inhibitory currents in NTS-VLM neurons of SH rats was reduced and not accompanied by any change in rise-time and decay-time; (b) the 1/CV2 and the number of failures in response to evoked currents were also affected by SH; (c) the frequency of spontaneous inhibitory currents was reduced by SH without changes in amplitude and half-width. These effects of SH were observed in NTS-VLM neurons located in caudal and intermediate NTS, but not in NTS-VLM neurons located in the rostral NTS. We conclude that SH causes a reduction in inhibitory modulation onto NTS-VLM neurons by pre-synaptic mechanisms, which may contribute to the observed changes in the respiratory pattern of Wistar-Hannover rats submitted to SH. (C) 2021 IBRO. Published by Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 18/15957-2 - Modulação astrocítica dos neurônios bulbares envolvidos com a geração e controle das atividades simpática e respiratória de roedores submetidos à hipóxia
• Beneficiário: Benedito Honorio Machado
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 19/21276-0 - Participação dos astrócitos na transmissão inibitória nas vias neurais do quimiorreflexo no NTS de ratos expostos hipóxia mantida
• Beneficiário: Júlio César Pascoaloti de Lima
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto