BRIEF ETHANOL EXPOSURE INDUCES BREATHING DEPRESSION AND A MARKED INCREASE IN APNEAS IN NEONATAL RATS

MACCHIONE, A.F.; ANUNZIATA, F; HAYMAL, BO; ABATE, P; MOLINA, JC

Puerto Varas

Encuentro; VIII LASBRA INTERNATIONAL MEETING: ?Neurobiological basis of alcoholism: from molecules to behavior?; 2017

The effects of early ethanol exposure upon neonatal respiratory plasticity have received progressive attention given a multifactorial perspective related with the Sudden Infant Death Syndrome or hypoxia-associated syndromes. This preclinical study was performed in rat neonates during the brain growth spurt period (postnatal days 3-9) which is equivalent to the 3rd human gestational trimester. Breathing rates and apneas were examined in pups receiving vehicle or a relatively moderate ethanol dose utilizing a whole body plethysmograph. Ethanol exposure progressively exerted a detrimental effect upon breathing patterns. A test conducted at PD 9 when pups were sober confirmed ethanol´s detrimental effects upon respiratory plasticity (breathing depression). Pre-exposure to the drug also resulted in a highly disorganized respiratory response following a hypoxic event characterized by heightened apneic episodes during a recovery normoxia phase. In a 2nd test conducted at PD 9 while pups were intoxicated and undergoing hypoxia, an attenuated hyperventilatory response was observed. In this test there were also indications that prior ethanol exposure depressed breathing rates during hypoxia and a recovery normoxia phase, without an increase in apneas. These results indicate that brief ethanol experience significantly disorganizes respiratory patterns. It causes respiratory depressions during and after a hypoxic event. This breathing anomaly was accompanied by a marked increase in the number of apneas during the recovery normoxia phase when pups were tested sober. These results indicate serious deleterious effects of the drug upon breathing patterns and the emergence of apneic episodes during a critical stage where respiratory plasticity is being structured.