Interaction between the retrotrapezoid nucleus/parafacial region and the kölliker-fuse area in the modulation of the respiratory pattern.

Author(s)

Elvis Viana de Lucena

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2015-06-09

Examining board members

Thiago dos Santos Moreira; Debora Rejane Fior Chadi; Mirela Barros Dias

• Advisor: Thiago dos Santos Moreira

Abstract

Breathing pattern is divided into 4 phases: pre-inspiration (PrI), inspiration (I), post-inspiration or first phase of expiration (PI/E1) and the active expiration (E2), and this phases are controlled by the central nervous system . Thus, the aim of this study was to investigate the involvement of this region in the control of PrI and PI activity in adult male Wistar rats (270-320 g, n = 5/group). Mean arterial pressure (MAP), the electromyographic activity of the genioglossus muscles (GGEMG), diaphragm (DiaEMG) and abdominal (AbdEMG) and the electrical activity of the vagus nerve were recorded in rats artificially ventilated and urethane anesthetized. Unilateral injection of NMDA (5 pmol/50 nl) in the pFRG/RTN of anesthetized animals was able to produce an increase in MAP (13 ± 6 mmHg), GGEMG (21 ± 3%), DiaEMG (25 ± 5%), and elicit an expiratory activity in the AbdEMG. In addition, pFRG/RTN stimulation increase post-inspiratory activity (57 ± 9%). Bilateral injection of muscimol (100 pmol/50 nl) into the KF eliminated the GGEMG (2 ± 2%), but only reduced the DiaEMG (12 ± 2%) and AbdEMG (111 ± 13%) induced by NMDA injection into the pFRG/RTN. Muscimol bilaterally into the KF was able to eliminate GGEMG (6 ± 4 vs. saline: 47 ± 9%) after hypercapnia (10% CO2). Muscimol into the KF reduced the DiaEMG (25 ± 6 vs. saline: 43 ± 8%) and AbdEMG (213 ± 23 vs. saline: 335 ± 18%) produced by hypercapnia. The results of the present study showed for the first time that the pFRG/RTN region it is not only involved in the control of inspiration and expiration, but shows to have a role in the pre- and post-inspiratory activity. Moreover, our work also presents evidence that these respiratory responses are modulated by KF network. (AU)

• FAPESP's process: 12/16166-2 - Involvement of the parafacial/retrotrapezoid nucleus in the control of upper airway
• Grantee: Elvis Viana de Lucena
• Support Opportunities: Scholarships in Brazil - Master