5-HT1A receptors of the lateral septum regulate inhibitory avoidance but not escape behavior in rats

5-HT1A receptors of the lateral septum regulate inhibitory avoidance but not escape behavior in rats

Author Barros Viana, Milena de Autor UNIFESP Google Scholar
Zangrossi, Helio Google Scholar
Massaro Onusic, Gustavo Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Universidade de São Paulo (USP)
Abstract Serotonin in the lateral septum (LS) has been implicated in the modulation of defensive behaviors and in anxiety. However, it is currently unknown whether changes in 5-HT mechanisms in this brain area may selectively affect defensive responses associated with specific subtypes of anxiety disorders recognized in clinical settings. To address this question, we evaluated the effect of the intra-LS injection of the 5-HT1A/7 receptor agonist 8-CH-DPAT (0.6, 3.0, 15.0 nmol) in male Wistar rats exposed to the elevated T-maze animal model of anxiety. This test allows the measurement of two behavioral defensive responses in the same rat: inhibitory avoidance and escape behavior. in clinical terms, these responses have been respectively related to generalized anxiety and panic disorder. the effects of 8-OH-DPAT were compared to those caused by a standard anxiolytic compound, the benzodiazepine receptor agonist midazolam (MDZ, 20 nmol). We also investigated whether the intra-LS injection of the 5-HT1A receptor antagonist WAY-100635 (0.37 nmol) was able to block the effects of 8-OH-DPAT. All animals were also tested in an open field for locomotor activity assessments. Results showed that whereas intra-LS administration of MDZ decreased avoidance latencies, suggesting an anxiolytic action, 8-OH-DPAT caused the opposite effect. Neither drug affected the escape performance. Intra-LS administration of WAY-100635 blocked the anxiogenic effect caused by 8-OH-DPAT. No changes to locomotion were detected in the open field. the data suggests that LS 5-HT1A receptors are involved in the control of inhibitory avoidance behavior and that a failure in this regulatory mechanism may be of importance to the physiopathology of generalized anxiety disorder. (c) 2008 Elsevier Inc. All rights reserved.
Keywords anxiety
lateral septum
5-HT1A receptors
elevated T-maze
Language English
Date 2008-05-01
Published in Pharmacology Biochemistry and Behavior. Oxford: Pergamon-Elsevier B.V., v. 89, n. 3, p. 360-366, 2008.
ISSN 0091-3057 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 360-366
Origin http://dx.doi.org/10.1016/j.pbb.2008.01.007
Access rights Closed access
Type Article
Web of Science ID WOS:000255311600016
URI http://repositorio.unifesp.br/handle/11600/30645

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