Differential effect of isolation in adulthood on frustration, anxiety and physical pain responses in rats.

LUCAS CUENYA, SANDRO FOSACHECA, GISELLE KAMENETZKY Y ALBA MUSTACA.

Huerta Grande, Córdoba, Argentina

Congreso; 1º Reunión Conjunta del Taller Argentino de Neurociencia y la Sociedad Argentina de Neuroquímica.; 2009

Previous research has demostrated that devaluation or omission of an expected reward has aversive properties, and suggest that the elicitated emotional state presents similar characteristics to anxiety responses and physical pain. Social isolation generates alterations in anxiety and pain reactions. Two experiments are presented. Their aims were to investigate the possible impact of isolation in adulthood on anxiety responses measured by the Elevated Plus Maze (EPM), sensibility to physical pain measured by the Hot Plate test (HP), and reactions to different situations of reward devaluation or omission in rats: the consummatory successive negative contrast (cSNC), the consummatory extinction (Ec), and the partial reinforcement effect on the incentive devaluation (PREID). In Experiment 1, sixty days old rats were randomly assigned to two housing conditions: grouped and isolated. The former were more active and showed less anxiety in comparison with the isolated ones in the EPM. Significant differences were not found in the cSNC, Ec and HP. In Experiment 2, isolated subjects presented less sensibility to physical pain in the HP, and no differences were found between conditions in the EPM and the PREID. As a whole, the results show that anxiety responses and sensibility to pain are affected by isolation, but reward devaluation and omission are not. The differences between physical and psychological pain and the implications of using isolation protocols at the frustration research are discussed.