Persistence of ethanol-induced tolerance during the preweanling period of the rat

CASTELLO, S.; DALOISIO, G; MOLINA, J.C.; ARIAS, C.

San Sebastian

Congreso; International Society for Developmental Psychobiology; 2015

We have recently reported that a high ethanol dose can induce toleranceto the locomotor stimulating effect of the drug in the infant rat.This effect is context-dependent, because it was exclusively observedwhen infants were trained and tested in the same context. The aimof the present study was two-fold. First, we explored the persistenceof the context-dependent tolerance across the preweanling period;and secondly, we assessed whether different reminder treatments reinstatetolerance after a long-time interval. Subjects were trainedwith ethanol during the 2nd or 3rd postnatal week of life, and 2 or7 days later they were tested in response to ethanol in terms of locomotoractivity (appropriate control groups were included in all the experiments).Our results showed tolerance only after 2 days of training,while 7 days later, instead of tolerance; sensitization induced by ethanolwas observed in both age groups. Finally we also found recovery oftolerance 7 days after training. Different contextual cues controlled allof these effects across ages. These results indicate that both, toleranceand sensitization can be induced during infancy by the same ethanolexperience, and that the short- and long-term expression of these processescan be modulated by different contextual treatments. The presentresults, in agreement with previous studies from our laboratory,show that ethanol during infancy can result in long-term effects thatmodulate reactivity to the drug later in development.