NEONATAL PRE-EXPOSURE TO ETHANOL INCREASES HYPERVENTILATION AND c-FOS ACTIVITY IN THE RESPIRATORY NETWORK DURING A HYPOXIC EVENT

MACCHIONE, A.F.; MOLINA, J.C.

Ribeirao Preto

Simposio; Behavioral Autonomic and Neuroendocrine Mechanisms Regulating Homeostasis: a Lifelong Perspectives.; 2016

Numerous studies show that exposure to a neuroteratogen such as alcohol during early ontogeny, generates a spectrum of alterations concerning the respiratory plasticity. Furthermore, early exposure to the drug is able to elicit functional impairments in the control of breathing responses that could result in hypoxic episodes. The aim of this study was to evaluate the impact of an ethanol dose (2.0g/kg, intragastrically) upon breathing responses in neonates (postnatal-day 9 -PD9) -under conditions of normoxia or hypoxia (O2-8%)- and as a function of prior ethanol exposure (PDs 3, 5 and 7). Fos-immunoreactivity was also quantified in central areas involved in breathing regulation (nucleus of the solitary tract -NTS and area postrema-AP). Our results indicate that, under normoxic conditions, animals pretreated with the drug showed a respiratory depression compared to controls. In contrast, when these animals were subjected to hypoxic conditions they exhibited higher levels of hyperventilation relative to controls. The highest rate of hyperventilation found in animals pre-exposed to ethanol, was associated with an increase in the number of Fosimmunoreactivecells in the NTS and AP. Afferent signals from baroreceptors, chemoreceptors and pulmonary receptors are processed in these nuclei, which regulate autonomic and respiratory activity under hypoxic conditions. Taken into account the correlation existing between ethanol intoxication and the occurrence of a hypoxic episode, it is possible to postulate that ethanol pre-exposure sensitizes the afferent pathways to NTS and AP when the organism suffers hypoxic episodes. This work was supported by grants from ANPCyT (PICT 2011 and 2014); CONICET and SECyT-UNC.