LESIONS EF THE PEDUNCLOPONTINE TEGMENTAL NUCLEUS INCREASE ANXIETY IN RATS

To test the hypothesis that the pedunclopontine tegmental nucleus (PPT g) plays a role in anxiety, rats with electrolytic lesions of the PPTg were tested in two animal models of anxiety, the elevated plus maze a nd the social interaction tests. Histological analysis showed that les ions were concentrated on the caudal half of the PPTg. In the elevated plus maze, traditional as well as 'risk assessment' measures indicate d significantly increased anxiety in the PPTg-lesioned rats us sham-op erated controls. In the social interaction test, behavioural scores we re biased towards elevated anxiety in the PPTg-lesioned rats but only the number of social sniffs reached significance. Our results confirm that electrolytic lesions of the caudal PPTg produce increased anxiety . (C) 1998 Rapid Science Ltd.