Neuroanatomical and physiological evidence that the retrotrapezoid nucleus/parafacial region regulates expiration in adult rats

作者：Silva Josiane N; Tanabe Fabiola M; Moreira Thiago S; Takakura Ana C^*

来源：Respiratory Physiology & Neurobiology, 2016, 227: 9-22.

DOI：10.1016/j.resp.2016.02.005

• Retrotrapezoid nucleus
• Active expiration
• Caudal ventral respiratory group
• Breathing
• Chemoreflex

The rostroventrolateral medulla contains two functional neuronal populations: (1) the parafacial respiratory group (pFRG) neurons and (2) the chemosensitive retrotrapezoid nucleus (RTN) neurons. Using anatomical and physiological techniques, we investigated the role of the RTN/pFRG in CO2-induced active expiration (AE) in urethane-anesthetized rats. Anterograde tracing using biotinylated dextran amine (BDA) revealed dense neuronal projections emanating from the RTN/pFRG to the caudal ventral respiratory group (cVRG), 60% of which contained vesicular glutamate transporter-2. The minority (16%) of the RTN projections to the cVRG emanated from Phox2b positive neurons. Hypercapnia (10% CO2) increased Dia(EMG) and elicited Abd(EMG) activity. Bilateral injections of muscimol (2 mM) into the RTN/pFRG reduced the activation of Dia(EMG) (23 4%) and abolished AE-induced by chemoreflex stimulation. Taken together, these results support the presence of direct excitatory projections from RTN/pFRG neurons to cVRG expiratory premotor neurons, playing a role in the generation/modulation of AE.

• 出版日期2016-6-15