Fos study of ponto-medullary areas involved in the in vitro hypoxic respiratory depression.

In this study, the brainstem-spinal cord preparation isolated from newborn rats, an established model for the study of the hypoxic respiratory depression (HRD), has been used. The comparison of Fos expression in ponto-medullary areas in these preparations placed either in normoxic or hypoxic conditions suggests that only the retrotrapezoid nucleus (RTN) and the ventrolateral medulla (VLM) are involved in the in vitro HRD. Hypoxic preparations exhibit a Fos expression enhanced in the RTN, suggesting that the RTN might play a crucial role in the HRD. As well as this, VLM neurons presented a decrease in Fos expression that could be related to the decline of the respiratory output induced by hypoxia.