Publikationsdatenbank

Anxiety but not arousal increases 5-HT release in rat hippocampus (2005)

Art

Poster

Autoren

Rex, A.

Voigt, J. P.

Fink, H.

Kongress

8th World Congress of Biological Psychiatry

Wien/Österreich, 28.06. – 03.07.2005

Quelle

The world journal of biological psychiatry

Bandzählung: Vol. 6

Heftzählung: Suppl. 1

Seiten: 334 – 335

ISSN: 1814-1412

Sprache

Englisch

Kontakt

Institut für Pharmakologie und Toxikologie

Koserstr. 20
14195 Berlin
+49 30 838 53221
pharmakologie@vetmed.fu-berlin.de

Abstract / Zusammenfassung

Anxiety but not arousal increases 5-HT release in rat hippocampus

Objectives: The central serotonergic system is involved in the aetiology of numerous disease states, including depression and anxiety disorders. Drugs that alter serotonin (5-HT) function are the frontline treatment of anxiety disorders. Several studies have shown that exposure of rats to animal tests for anxiety increases extracellular 5-HT in the cortex or the hippocampus.
Aim of the study is to discriminate whether the increase in extracellular 5-HT is caused by aversive conditions of an animal test for anxiety or by an unconditioned stressor evoking arousal.
Methods: The present study investi¬gates the effects of exposure to an acoustic stimulus (95 dB) or to the ele¬vated plus maze (X-maze, illumination: 210 lux open arms, 160 lux closed arms) or to a X-maze with closed arms only (C-maze), for 20 minutes respectively, on 5-HT relea¬se in the ventral hippocampus of rats, determined by in vivo microdialysis followed by HPLC and electrochemical detection.
Results: Exposure of male Fischer 344 rats (Charles River, Germany, 220±30 g) to the X-maze induced an ‘anxious’ behaviour and increased extracellular 5 HT to 165% of basal release. However, exposure to white noise in the familiar surroundings of the home cage did not change extracellular 5-HT in the hippocampus, even though locomotor activity and the percentage of animals digging in the bedding were increased.
Conclusions: The increased 5-HT release concurred with exposure to the X maze but not to the less aversive but new surroundings of the C-maze with or exposure to white noise. This indicates a strong relationship between 5-HT release and behaviour indicative of "anxiety". Our results are backed up by recent studies showing ‘anxiolytic’ effects of Neuropeptide S accompanied by increased motor activity. It is suggested that the relationship between arousal/non-specific behavioural activation and 5-HT in general is not necessarily linked in the rat hippocampus.