RESPIRATORY PLASTICITY AND ETHANOL-RELATED LEARNING AS A FUNCTION OF EARLY ACETALDEHYDE EXPOSURE IN NEONATE RATS

ACEVEDO, M. B. 1; PEPINO, Y. 1; HAYMAL, O. B.2; D'ALOISIO, G. 2; MOLINA J.C. 2

Denver Colorado

Congreso; 40th Annual Scientific Meeting of the Research Society on Alcoholism; 2017

Research Society on Alcoholism

Prior studies indicate that neonates are very sensitive to ethanol?s positive reinforcing effects and toits depressant effects upon breathing. Acetaldehyde (ACD) appears to play a major role in terms ofmodulating early reinforcing effects of the drug. Yet, there is no pre-existing literature relative to theincidence of this metabolite upon respiratory plasticity. The present study analyzed physiological andbehavioral effects of early central administrations of ethanol, acetaldehyde or vehicle. Respirationrates (breaths/min) were registered at postnatal days (PDs) 2 and 4 (post-administration time: 5, 60or 120 minutes). At PD5, all pups were placed in a context (plethysmograph) where they had previouslyexperienced the effects of central administrations and breathing patterns were recorded. Followingthis test, pups were evaluated using and operant conditioning procedure where ethanol orsaccharin served as positive reinforcers. Body temperatures were also registered prior to drugadministrations as well as at the beginning and the end of each specific evaluation. Across days,breathing responses were high at the beginning of the evaluation session and progressively declinedas a function of the passage of time. At PDs 2 and 4, shortly after central administration (5 min),ACD exerted a significant depression upon respiration frequencies. Ethanol-administered pupsshowed this depression when evaluated at a later post-administration time (120 min). At PD5, nonintoxicatedpups with a prior history of ACD central administrations, exhibited a marked increase inrespiratory frequencies; a result that probably indicates a conditioned compensatory response.When operant testing procedures were conducted, prior ethanol or ACD central administrations werefound to inhibit the reinforcing effects of ethanol. This was not the case when saccharin wasemployed as a reinforcer. As a whole, the results indicate a significant role of central ACD upon respiratoryplasticity of the neonate and upon ethanol?s reinforcing effects; phenomena that affect thephysiological integrity of the immature organism and its subsequent affinity for ethanol operationalizedthrough self-administration procedures.