Noradrenergic mechanisms in the retrotrapezoid nucleus in the control of chemoreception

• Grant number: 13/26540-1
• Support Opportunities: Scholarships in Brazil - Master
• Start date: June 01, 2014
• End date: November 30, 2015
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Ana Carolina Takakura Moreira
• Grantee: Luiz Marcelo Oliveira Santos
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Breathing is controlled by a complex network located in the Ventrolateral Respiratory Group (VRG), and modulated by other important regions, such as Retrotrapezoid Nucleus (RTN). The RTN is the main source of central chemoreceptors and is high sensitive to increase in arterial partial pressure of CO2 (hypercapnia) and reduction in pH in vivo. Noradrenaline´s application and action in respiratory control is controversial; however, studies performed in other neural regions showed specific actions modulated by ±-1 or ±-2 adrenoceptors. Besides, previous studies showed the presence of PNMT-varicosities in the RTN region. In this way, it is important to investigate the respiratory effects produced by injection of noradrenaline in the RTN and the adrenoceptors involved in these effects. It is also important to investigate the source of this noradrenergic input to RTN region. The experiments will be performed in adult male Wistar rats (250-300g) anesthetized with urethane. The animals will be subjected to the following surgical procedures: artery and vein cannulation, removal of the occipital plate to insert cannula and electrode coupled to diaphragm and abdominal muscle. It will be recorded blood pressure and electromyography activity of the muscles involved in breathing (diaphragm and abdominal) in two situations: after unilateral injection of saline or noradrenaline into the RTN during hypercapnia or unilateral injection of noradrenaline into the RTN before and after bilateral blockade of ±-1 or ±-2 adrenoceptors in the RTN. In another group of animals, it will be studied the noradrenergic projections to RTN by injecting a retrograde tracer (Fluorgold-FG) in the RTN. It will be quantified the presence of cell bodies containing FG in the different noradrenergic nuclei within the central nervous system. At the end of the experiments, the animals will be sacrified, perfused and the brain will be removed to immunohistochemistry proccess. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

KUO, FU-SHAN; FALQUETTO, BARBARA; CHEN, DAWEI; OLIVEIRA, LUIZ M.; TAKAKURA, ANA C.; MULKEY, DANIEL K.. In vitro characterization of noradrenergic modulation of chemosensitive neurons in the retrotrapezoid nucleus. Journal of Neurophysiology, v. 116, n. 3, p. 1024-1035, SEP 2016. (13/26540-1)

OLIVEIRA, LUIZ M.; MOREIRA, THIAGO S.; KUO, FU-SHAN; MULKEY, DANIEL K.; TAKAKURA, ANA C.. alpha(1)- and alpha(2)-adrenergic receptors in the retrotrapezoid nucleus differentially regulate breathing in anesthetized adult rats. Journal of Neurophysiology, v. 116, n. 3, p. 1036-1048, SEP 2016. (13/10573-8, 13/26540-1, 14/22406-1)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

SANTOS, Luiz Marcelo Oliveira. Adrenergic mechanisms in the retrotrapezoid nucleus in breathing control.. 2015. Master's Dissertation - Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI) São Paulo.