INHIBITION OF THE PONTINE KOLLIKER-FUSE NUCLEUS REDUCES GENIOGLOSSAL ACTIVITY ELICITED BY STIMULATION OF THE RETROTRAPEZOID CHEMORECEPTOR NEURONS

Author(s)

Silva, Josiane N. ^[1] ; Lucena, Elvis V. ^[2] ; Silva, Talita M. ^[2] ; Damasceno, Roselia S. ^[2] ; Takakura, Ana C. ^[1] ; Moreira, Thiago S. ^[2]

Affiliation

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Pharmacol, BR-05508000 Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Inst Biomed Sci, Dept Physiol & Biophys, BR-05508000 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Neuroscience; v. 328, p. 9-21, JUL 22 2016.
• Web of Science Citations: 8

Abstract

The Kolliker-Fuse (KF) region, located in the dorsolateral pons, projects to several brainstem areas involved in respiratory regulation, including the chemoreceptor neurons within the retrotrapezoid nucleus (RTN). Several lines of evidence indicate that the pontine KF region plays an important role in the control of the upper airways for the maintenance of appropriate airflow to and from the lungs. Specifically, we hypothesized that the KF region is involved in mediating the response of the hypoglossal motor activity to central respiratory chemoreflex activation and to stimulation of the chemoreceptor neurons within the RTN region. To test this hypothesis, we combined immunohistochemistry and physiological experiments. We found that in the KF, the majority of biotinylated dextran amine (BDA)-labeled axonal varicosities contained detectable levels of vesicular glutamate transporter-2 (VGLUT2), but few contained glutamic acid decarboxylase-67 (GAD67). The majority of the RTN neurons that were FluorGold (FG)-immunoreactive (i.e., projected to the KF) contained hypercapnia-induced Fos, but did not express tyrosine hydroxylase. In urethane-anesthetized sino-aortic denervated and vagotomized male Wistar rats, hypercapnia (10% CO2) or N-methyl-D-aspartate (NMDA) injection (0.1 mM) in the RTN increased diaphragm (Dia(EMG)) and genioglossus muscle (GG(EMG)) activities and elicited abdominal (Abd(EMG)) activity. Bilateral injection of muscimol (GABA-A agonist; 2 mM) into the KF region reduced the increase in DiaEMG and GG(EMG) produced by hypercapnia or NMDA into the RTN. Our data suggest that activation of chemoreceptor neurons in the RTN produces a significant increase in the genioglossus muscle activity and the excitatory pathway is dependent on the neurons located in the dorsolateral pontine KF region. (C) 2016 IBRO. Published by Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 12/03568-5 - Anatomic projections between retrotrapezoid nucleus and caudal ventral respiratory group
• Grantee: Josiane do Nascimento Silva
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 10/09776-3 - Neural mechanisms involved in expiratory rhythm generator: possible involvement of the retrotrapezoid nucleus and the parafacial region
• Grantee: Ana Carolina Takakura Moreira
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 13/10573-8 - Ventral surface chemoreceptor neuronal mechanisms
• Grantee: Thiago dos Santos Moreira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 09/54888-7 - Neural mechanisms involved on chemoreception
• Grantee: Eduardo Colombari
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 13/00401-5 - Integration between rostroventrolateral medulla and paraventricular nucleus during arterial chemoreceptor activation: possible involvement of catecholaminergic mechanisms
• Grantee: Talita de Melo e Silva
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 10/15692-7 - Involvement of the Kolliker-Fuse in cardiorespiratory control during activation of central and peripheral chemoreceptors
• Grantee: Rosélia dos Santos Damasceno
• Support Opportunities: Scholarships in Brazil - Doctorate
• 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