Sex differences in adult Wistar rats in the voluntary consumption of ethanol after pre-exposure to ethanol-induced flavor avoidance learning.

Vulnerability to ethanol abuse may be a function of the balance between the opposing (aversive and rewarding) motivational effects of the drug. The study of these effects is particularly important for understanding alcohol addiction. Research in this field seems to point out that ethanol effects are determined by a set of internal factors (sex, ethanol intake history, etc.

Control of food intake by MC4-R signaling in the lateral hypothalamus, nucleus accumbens shell and ventral tegmental area: interactions with ethanol.

The melanocortin system is involved in animal models of obesity and anorexia-cachexia and MC4 receptors (MC4-R) are currently a target system for the development of drugs aimed to treat obesity and eating disorders in humans. Previous evidence suggest that feeding peptides might lack their orexigenic activity while stimulate ethanol intake. The present study comparatively evaluated food intake (4-h interval) in Sprague-Dawley (SD) rats drinking ethanol (6% w/v, 2 bottle choice paradigm) (EE group) and ethanol-naïve (EN) rats in response to bilateral infusion of the selective MC4-R antagonist HS014 (0, 0.

One-way avoidance learning in female inbred Roman high- and low-avoidance rats: effects of bilateral electrolytic central amygdala lesions.

Female inbred Roman high- (RHA-I) and low- (RLA-I) avoidance rats show differences in one-way avoidance learning only when the task implies a highly aversive situation (1s in the "non-shock"-associated safe compartment, as opposed to 30s). These between-strain differences seem to depend on strain differences in emotionality, given that: (i) they are abolished by IP administration of the GABAergic anxiolytic diazepam (Torres et al. [32]) and (ii) avoidance responding appears to correlate with cellular density in the basolateral amygdala (Gómez et al.

Consummatory successive negative and anticipatory contrast effects in inbred Roman rats.

Three experiments were designed to study the performance of female inbred Roman High-(RHA-I) and Low-(RLA-I) Avoidance rats in a consummatory task in which successive negative (cSNC) and anticipatory contrast (cANC) effects were induced by changing the concentration of the sucrose solution used as reward. Both RHA-I and RLA-I rats showed a significant suppression of drinking (cSNC) when they were exposed to 32% sucrose in preshift phase and 4% in postshift phase, in comparison to RHA-I and RLA-I control groups always exposed to 4% sucrose (Experiment 1). By contrast, when the preshift-postshift reward discrepancy was reduced from 32-4 to 22-4 in Experiment 2, both strains showed a suppression of fluid intake on the first postshift trial, whereas only the more emotional RLA-I strain maintained this suppression on subsequent days.

One-way avoidance acquisition and cellular density in the basolateral amygdala: strain differences in Roman high- and low-avoidance rats.

The goal of the present experiment was to study the performance of inbred Roman high- (RHA-I) and low- (RLA-I) avoidance rats in one-way avoidance learning and to relate the behaviour of the animals to cellular density in the basolateral amygdala (BLA), a brain region related to fear and anxiety. Thus, females from both strains were exposed either to 30s or 1s in the safe place as a function of experimental condition, until they reached five consecutive avoidance responses. Thereafter, the rats were perfused, and their brains sectioned in 40microm coronal sections, stained with cresyl violet.

The partial reinforcement extinction effect (PREE) in female Roman high- (RHA-I) and low-avoidance (RLA-I) rats.

The present experiment was designed with the goal of studying the partial reinforcement extinction effect (PREE) in female inbred Roman high- (RHA-I) and low-avoidance (RLA-I) rats. Two groups of RHA-I and two of RLA-I food-deprived animals were placed in a straight alley where they were partially or continuously reinforced. Once the animals reached the acquisition criterion, they were exposed to an extinction phase where the reinforcement was omitted.

Successive negative contrast effect in instrumental runway behaviour: a study with Roman high- (RHA) and Roman low- (RLA) avoidance rats.

It has been recently shown that Roman high- (RHA) and low- (RLA) avoidance rats show behavioural divergence in successive negative contrast (SNC) induced in one-way avoidance learning [Torres C, Cándido A, Escarabajal MD, de la Torre L, Maldonado A, Tobeña A, et al. Successive negative contrast effect in one-way avoidance learning in female roman rats. Physiol Behav 2005;85:377-82].

One-way avoidance learning and diazepam in female roman high-avoidance and low-avoidance rats.

The goal of this experiment was to study the influence of the time spent in the safe compartment (30 vs. 1 s) and of an intraperitoneal injection of diazepam (1 mg/kg vs. vehicle) on one-way avoidance learning, in inbred female roman high-avoidance and roman low-avoidance rats.