Participation of parafacial respiratory group in the orofacial and nasofacial motor responses of rats induced by activation of peripheral and central chemoreceptors

• Grant number: 16/24994-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2017
• End date: December 31, 2017
• Field of knowledge: Biological Sciences - Biophysics - Cellular Biophysics
• Principal Investigator: Davi José de Almeida Moraes
• Grantee: Alan Andrade de Britto
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 13/10484-5 - Electrophysiological and molecular characterization of neurons involved in the generation of respiratory rhythm and pattern of rats during postnatal development, AP.JP

Abstract

Expiration is a passive process, in other words, the activity of the abdominal muscles at this phase of the respiratory cycle is not very expressive. However, under conditions of metabolic challenges, such as in conditions of reductions in O2 partial pressure (activation of peripheral chemoreceptors) or increases in CO2 partial pressure increase (activation of central chemoreceptors) in arterial blood, expiration becomes active or forced, resulting in a large increase in the activity of the abdominal muscles. Active expiration in rats seems to be mediated by neurons of the parafacial Respiratory Group (pFRG) called late-expiratory (late-E), located mainly adjacent to the ventrolateral portion of the facial nucleus in the brainstem. Active expiration, nevertheless, requires more than simply promoting contractile activity of the abdominal muscles, it is also necessary to generate contraction of the laryngeal intrinsic muscles, facial muscles responsible by moving the nostrils and muscles that control the opening and closing of the jaw to regulate airways resistance and airflow. In this regard, the hypothesis of this project is that the pFRG neurons project to the motoneurons of trigeminal motor nucleus and facial nucleus to control orofacial and nasofacial motor behaviors of rats, respectively, in response to the activation of central and peripheral chemoreceptor. To test this hypothesis, we will perform electrophysiological records of motor nerves (buccal and zygomatic branches of the facial nerve; mylo-hyoid branch of the trigeminal nerve) involved in orofacial and nasofacial motor behaviors, as well as motoneurons of trigeminal motor nucleus and facial nucleus in in situ preparations of rats during activation of central and peripheral chemoreceptors, as well as in response to activation and inhibition of pFRG neurons. We will also use viral vectors to analyze neural pathways that are involved in respiratory modulation of orofacial and nasofacial behaviors. Therefore, the results to be obtained with this project may provide important information about the respiratory modulation, and the underlying neural substrates, of the nasofacial and orofacial motor behaviors of rats. (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)

MAGALHAES, KAROLYNE S.; DE BRITTO, ALAN A.; PATON, JULIAN F. R.; MORAES, DAVI J. A.. A6 neurons simultaneously modulate active expiration and upper airway resistance in rats. Experimental Physiology, v. 105, n. 1, p. 53-64, JAN 2020. (17/09071-9, 16/24994-3, 13/10484-5)

DE BRITTO, ALAN A.; MAGALHAES, KAROLYNE S.; DA SILVA, MELINA P.; PATON, JULIAN F. R.; MORAES, DAVI J. A.. Active expiratory oscillator regulates nasofacial and oral motor activities in rats. Experimental Physiology, v. 105, n. 2, JAN 2020. (15/01073-7, 13/10484-5, 17/09071-9, 16/24994-3)