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Lesions of the pedunclopontine tegmental nucleus increase anxiety in rats

Podhorna, Jana1; Franklin, Keith B. J.1,2

Motivation, Emotion, Feeding, Drinking, Sexual Behaviour

TO test the hypothesis that the pedunclopontine tegmental nucleus (PPTg) plays a role in anxiety, rats with electrolytic lesions of the PPTg were tested in two animal models of anxiety, the elevated plus maze and the social interaction tests. Histological analysis showed that lesions were concentrated on the caudal half of the PPTg. In the elevated plus maze, traditional as well as ‘risk assessment’ measures indicated significantly increased anxiety in the PPTg-lesioned rats vs sham-operated controls. In the social interaction test, behavioural scores were 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.

1Department of Psychology, McGill University, 1205 Dr Penfield Avenue, Montreal, QC H3A 1B1, Canada.

2Corresponding Author: Keith B. J. Franklin

ACKNOWLEDGEMENTS: This research was supported by grants from the Natural Sciences and Engineering Research Council of Canada and the program Formation de Chercheurs et L'Aide à la Recherche du Quebec. J.P. was a PDF supported by the W Stairs memorial Fund of McGill University.

Received 24 February 1998; accepted 19 March 1998

© Lippincott-Raven Publishers.