Changes in glutamatergic neurotransmission in the nucleus tractus solitarius of rats submitted to sustained hypoxia are related to the inflammatory process

Author(s)

Ludmila Lima Silveira

• Document type: Doctoral Thesis
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
• Defense date: 2018-05-18

Examining board members

Benedito Honório Machado; Luciane Helena Gargaglioni Batalhão; Ricardo Mauricio Xavier Leão; Thiago dos Santos Moreira; Fernanda Luciano Rodrigues

• Advisor: Benedito Honório Machado

Abstract

Short-term Sustained hypoxia (SH) is associated with cardiorespiratory changes and inflammatory process in humans and experimental models. There is also evidence that SH can change the synaptic transmission in the nucleus tractus solitarius (NTS) region. Here we use the minocycline, an anti-inflammatory and microglial inhibitor, to evaluate the role of inflammation triggered by SH on the excitatory neurotransmission in the NTS neurons sending projections to the ventrolateral medulla (NTS-VLM). We hypothesized that SH induces brainstem inflammatory process, which may contribute to increase in excitatory neurotransmission and excitability of the NTS-VLM neurons, collaborating to the high blood pressure observed on these rats. Although we have observed increased MAP in both groups of rats treated with vehicle (saline + distilled water, i.p) or minociclina [(30mg/Kg i.p for 3 days) submitted to 24h of SH (FiO2 0.1) in relation to their respective control groups (FiO2 0.28), the MAP increase was lower in rats treated with minociclina. The whole cell patch-clamp recordings showed that SH produced no changes in active properties of NTS neurons. However, neurons of rats submitted SH presented an increase in the glutamatergic neurotransmission and the number of microglial at the NTS region. These increases were prevented in the groups previously treated with minociclina. We conclude that inflammation induced by SH contributes to the increased excitatory neurotransmission in NTS-VLM neurons that could be associated to high blood pressure observed in these rats. (AU)

• FAPESP's process: 14/11101-5 - The influence of inflamatory process on the activity of nucleus tractus solitarius neurons in juvenile rats submitted to sustained hypoxia
• Grantee: Ludmila Lima Silveira
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)