Effects of an Aversive Memory on the Rewarding Effects of Ethanol in Ethanol Dependent Rats
Boiero C, Bertotto ME, Molina VA and Martijena ID.
IFEC-CONICET. Departamento de Farmacología. FCQ. UNC. 5000. Córdoba, Argentina. cboiero@fcq.unc.edu.ar
Stress has been shown to facilitate the rewarding effects of drugs of abuse including ethanol (ETOH). We have previously shown that retrieval of fear memory facilitates subsequent ETOH consumption in ETOH withdrawn rats. Given that the rewarding properties of ETOH might be involved in such increased ETOH intake, the effect of retrieval of fear memory on the rewarding properties of ethanol was assessed using the conditioned place preference (CPP) paradigm. Male Wistar rats were allowed to consume an ethanol-containing liquid diet (6% v/v) for 14 days. After 72 h of withdrawal, the pre-conditioning session for CPP was performed (10 min). The next day, one group of rats was exposed to 3 footshocks (0.4mA, 3s, 30 s intershock interval). The CPP conditioning began 24 h after fear training and rats received 4 saline and 4 ETOH pairings (1 g/kg, ip) on alternating days into the assigned CPP compartment for 8 min. One day after of the last ETOH injection, the contextual fear response was evaluated 2 h prior to the CPP test (10 min). Consistent with previous work, ETOH withdrawn rats showed an enhanced contextual fear response. ETOH produced neither CPP nor place aversion in both control and ETOH withdrawn non-fear trained rats. However, significant CPP for ETOH was induced following retrieval of contextual fear memory in ETOH withdrawn rats. These data suggest that an aversive memory can affect the motivational properties of ETOH in withdrawn rats.
