The objectives of the present work were to study the influence of ethanol withdrawal on: 1) fear response, as an expression of associative and non-associative aversive learning; 2) the extinction process of conditioned freezing and 3) the effect of D-cycloserine (DCS, a partial NMDA agonist) on extinction of conditioned freezing.
Adults male Wistar rats were submitted to chronic treatment with an ethanol (6% v/v) liquid diet for 12 days. Rats were exposed to 3 inescapable electrical foot-shocks (0.7mA, duration 3 s; conditioning), on the third day of abstinence. Twenty-four, 48, 72 and 96 h later animals were exposed to the context without shock delivery, for 10 min (extinction training). One group of animals were injected with DCS (5 mg/kg i.p) immediately after the first session of extinction training. Ethanol withdrawn animals showed an enhanced associative aversive learning and a marked resistance to extinguish such emotional response. A facilitatory effect of DCS on the extinction process was observed only in ethanol withdrawn animals.
