Early ethanol exposure effects in hypoxic conditions on 5HT levels at medullary raphe in neonate rats.

GIACINTO, C.; PALMERI, T.; MACCHIONE, A.F.

Encuentro; Encuentro SAN; 2022

Ethanol is commonly consumed during gestation and lactation, impacting on thefetus and neonate. EtOH affects neurovegetative functions, such as breathing. Oneof the main ethanol targets on the CNS is the serotonin (5HT) neurons that also areinvolved in breathing modulation. Preclinical studies, that employ chronic and severeEtOH consumption during pregnancy and lactation, showed a decrease in thenumber of 5HT-neurons and 5HT levels in the raphe system. However, the status ofthe 5HT-system in animal models with low/moderate neonatal EtOH exposure areunderstudied. In previous studies we found that the first EtOH intoxication decreasesthe 5HT levels in the raphe obscurus-ROb, but the pre-exposure to the drug inducesa compensatory effect unaltering the 5HT levels in this area. In this study weevaluate 5HT levels by immunofluorescence in other areas of the medullary raphe(ROb, magnus and pallidus) in neonate rats exposed to EtOH and challenged withhypoxia (3 episodes of 5 min). At postnatal days-PD 3, 5 and 7, pups wereadministered with EtOH or vehicle (2.0 or 0.0g/kg, ig). At PD 9, pups were EtOHre-intoxicated or not (vehicle-administered). This design allows us to discriminate theeffects of EtOH pre-exposure from those of acute EtOH intoxication. These resultsbecome important when associating the function of the medullary raphe onrespiratory response and breathing disturbances induced by EtOH in neonate ratsand humans, such as Sudden Infant Death Syndrome.