ETHANOL DRINKING PATTERN DIFFERENTLY AFFECTS NOVELTY-RELATED BEHAVIOUR DURING ABSTINENCE IN FEMALE RATS

Abstract

Withdrawal from chronic ethanol leads to a multifaceted syndrome, characterized by negative affective state. Novelty seeking and motivation, closely related to affective state, can be assessed in rodents exploring behavioural response to novelty. This study aims at assessing novelty-related behaviour in female rats during ethanol withdrawal following different self-administration patterns. Female rats underwent 9-week-, 2-bottle choice-, continuous or intermittent (3 days/week) access to 20% ethanol; they were named CARs and IARs respectively. After 12h from last ethanol access, they were tested for locomotor activity induced by a novel environment; time spent in the central area of an open field; novel object exploration and novelty preference. At the end of the paradigm IARs displayed greater ethanol intake (p<0.001) and preference with respect to CARs (p<0.001). In the open field test, CARs showed no differences in locomotor response to a novel environment, but displayed a lower number of central transitions (p<0.05) and time spent in the centre (p<0.05) than controls. IARs did not differ from controls in locomotor activity and central behaviour. Both groups displayed a lower object exploration time (p<0.001; p<0.05), and novelty preference (p<0.01; p<0.05) than controls, with CARs displaying the greater reduction. The present results indicate that abstinence from chronic ethanol decreases behavioural response to novelty in female rats, likely promoting an anxiogenic response to a novel situation, as observed in CARs, or a reduced motivation to approach to novelty, in IARs.