Learning experiences comprising central ethanol exposure in rat neonates: Effects upon respiratory plasticity and the brain catalase system.

TRUJILLO, VERÓNICA; DEZA PONZIO, R.; ALBRETCH, PAULA ALEJANDRA; MOLINA, J.C.; MACCHIONE, A.F.; VIRGOLINI, M.B.

CORDOBA

Congreso; IX LASBRA INTERNATIONAL MEETING; 2019

LATIN AMERICAN SOCIETY FOR BIOMEDICAL RESEARCH ON ALCOHOLISM

Fetal ethanol (EtOH) exposure represents a risk factor for the Sudden InfantDeath Syndrome and it?s early effects upon respiration also promotes hypoxicischemic consequences. This study analyzes central ethanol?s effects uponbreathing plasticity during a stage in the development of the rat equivalent to the3rd human gestational trimester. The study not only analyzed ethanol?sunconditioned breathing effects but also how they are regulated by learningprocesses. Taking into account that ethanol is primarily metabolized in the brainvia the catalase system, we examined the effects of early history with the drugupon the activity of this enzymatic system. During postnatal days 3, 5 and 7 (PDs3-7) pups either received intracisternal (i.c.) administrations of vehicle or ethanol(300 mg%). They were subsequently exposed to a whole body plethysmographunder normoxia. The apparatus was scented or not with the ethanol odor. Thepresence of the odorant increased breathing rates. The state of intoxicationattenuated the onset of apneas; a phenomenon indicative of an antianxiety effectof the drug given the state of arousal caused by the novel environment, maternaldeprivation and the stress of i.c. administrations. At PD9, pups were tested whilesober under sequential air conditions (initial-normoxia, hypoxia and recoverynormoxia). Once again the plethysmograh was unscented or contained EtOHodor. Prior experience with the scented chamber associated with EtOH?s centraleffects elicited a conditioned isodirectional response relative to the onset ofapneas previously observed during PDs 3-7. Yet, prior history with the drugexacerbated the onset of apneas when pups were defied with hypoxia. Followingthis test, pups ingested 0.8 g/kg of absolute EtOH and their brains were analyzedto determine catalase activity. Pre-exposure to EtOH?s central effects paired withthe odor of the drug resulted in heightened enzymatic activity. The resultsindicate that central EtOH accumulation may exert antianxiety effects thatattenuate apneic disruptions but that also has long-lasting effects uponrespiratory plasticity under hypoxia. Most importantly, these effects appear to berelated with how the brain catalase system reacts to the presence of EtOH inaccordance with the nature of prior experiences with the drug.