Active expiratory oscillator regulates nasofacial and oral motor activities in rats

Autor(es)

de Britto, Alan A. ^[1] ; Magalhaes, Karolyne S. ^[1] ; da Silva, Melina P. ^[1] ; Paton, Julian F. R. ^[2] ; Moraes, Davi J. A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Physiol, BR-14049900 Ribeirao Preto, SP - Brazil

^[2] Univ Auckland, Dept Physiol, Fac Med & Hlth Sci, Pk Rd, Auckland - New Zealand

• Tipo de documento: Artigo Científico
• Fonte: Experimental Physiology; v. 105, n. 2 JAN 2020.
• Citações Web of Science: 0

Resumo

New Findings What is the central question of this study?Does the parafacial respiratory group (pFRG), which mediates active expiration, recruit nasofacial and oral motoneurons to coordinate motor activities that engage muscles controlling airways in rats during active expiration. What is the main finding and its importance?Hypercapnia/acidosis or pFRG activation evoked active expiration and stimulated the motoneurons and nerves responsible for the control of nasofacial and oral airways patency simultaneously. Bilateral pFRG inhibition abolished active expiration and the simultaneous nasofacial and oral motor activities induced by hypercapnia/acidosis. The pFRG is more than a rhythmic oscillator for expiratory pump muscles: it also coordinates nasofacial and oral motor commands that engage muscles controlling airways. Active expiration is mediated by an expiratory oscillator located in the parafacial respiratory group (pFRG). Active expiration requires more than contracting expiratory muscles as multiple cranial nerves are recruited to stabilize the naso- and oropharyngeal airways. We tested the hypothesis that activation of the pFRG recruits facial and trigeminal motoneurons to coordinate nasofacial and oral motor activities that engage muscles controlling airways in rats during active expiration. Using a combination of electrophysiological and pharmacological approaches, we identified brainstem circuits that phase-lock active expiration, nasofacial and oral motor outputs in an in situ preparation of rat. We found that either high chemical drive (hypercapnia/acidosis) or unilateral excitation (glutamate microinjection) of the pFRG evoked active expiration and stimulated motoneurons (facial and trigeminal) and motor nerves responsible for the control of nasofacial (buccal and zygomatic branches of the facial nerve) and oral (mylohyoid nerve) motor outputs simultaneously. Bilateral pharmacological inhibition (GABAergic and glycinergic receptor activation) of the pFRG abolished active expiration and the simultaneous nasofacial and oral motor activities induced by hypercapnia/acidosis. We conclude that the pFRG provides the excitatory drive to phase-lock rhythmic nasofacial and oral motor circuits during active expiration in rats. Therefore, the pFRG is more than a rhythmic oscillator for expiratory pump muscles: it also coordinates nasofacial and oral motor commands that engage muscles controlling airways in rats during active expiration. (AU)

• Processo FAPESP: 15/01073-7 - Caracterização eletrofisiológica de motoneurônios expiratórios de ratos submetidos a hipóxia mantida
• Beneficiário: Melina Pires da Silva
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 13/10484-5 - Caracterização eletrofisiológica e molecular dos neurônios envolvidos na geração do ritmo e do padrão respiratório de ratos durante o desenvolvimento pós-natal
• Beneficiário: Davi José de Almeida Moraes
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 17/09071-9 - Participação dos neurônios noradrenérgicos do locus coeruleus na geração central das atividades inspiratória e expiratória em resposta à ativação dos quimiorreceptores centrais de ratos.
• Beneficiário: Karolyne Silva Magalhães
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 16/24994-3 - Participação do grupo respiratório parafacial nas respostas motoras orofaciais e nasofaciais de ratos induzidas pela ativação dos quimiorreceptores centrais e periféricos
• Beneficiário: Alan Andrade de Britto
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica