INIMEC - CONICET   05467
INSTITUTO DE INVESTIGACION MEDICA MERCEDES Y MARTIN FERREYRA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
AN INFANT MODEL OF ETHANOL SELF-ADMINISTRATION: INVOLVEMENT OF THE OPIOID SYSTEM.
Autor/es:
MIRANDA MORALES RS; MOLINA JC; ABATE P
Reunión:
Congreso; 2010 Scientific Meeting of the Research Society on Alcoholism. RSA, EEUU, 2010; 2010
Resumen:
The main goal of this study was to analyze appetitive and consumatory behaviors in an infantmodel of ethanol self-administration. Through the use of a non-selected antagonist, weevaluated how the opioid system modulates such behaviors.In a first experiment infant rats (PD14) were trained in an operant learning task to obtainsucrose 5% (Group 1), ethanol 3.75% (Group 2) or distilled water (Group 3). Yoked controlpups received the reinforcer each time the experimental pup was rewarded. Each trainingsession was performed in 15 minute, during 4 consecutive days (PDs 14, 15, 16 and 17). OnPD18 infants were evaluated in an extinction session.All experimental pups rapidly acquired an operant response across training days to gainaccess to the reinforcers. Paired pups significantly increased operant responses incomparison with yoked animals. Even when water elicited operant behavior, sucrose andethanol promoted higher levels of responses than this liquid. When analyzing operantbehavior, in the extinction session, paired pups previously infused with sucrose or ethanolexecuted a significant higher number of operant responses than pups infused with water(whose operant behavior was not different to the control pup). In a second experiment weevaluated the involvement of the opioid system in the pattern of infantile operant behaviormediated by ethanol and sucrose. Pups were trained in a similar operant learning task toobtain sucrose 5% (Group 1) or ethanol 3.75% (Group 2). At PDs 16 and 17, previousoperant session, animals were briefly re-exposed to sucrose or ethanol (5 minute of pulsatileinfusions, 1.5 second each) under opioid antagonism (naloxone) effects. Operant respondingfor sucrose or ethanol was then assessed. As previously observed, paired pups learned anoperant behavior either, for ethanol or sucrose. Nonetheless, during PDs 16 to 17, those pupsre-exposed to the reinforcer, under the effects of naloxone, failed to increase their operantresponse (neither for sucrose or ethanol), in comparison with their yoked controls. Duringextinction session, only a significant effect of learning condition was observed. Independentlyfrom the reinforcer received, paired pups elicited significantly more responses than yokedcontrols. These experiments indicate that ethanol and sucrose are potent reinforcers duringinfancy. The participation of the opioid system was possible to be observed only during theacquisition phase of this operant learning task.