Facilitation of contextual fear memory extinction and anti-anxiogenic effects of AM404 and cannabidiol in conditioned rats
Abstract The present study investigated the central effects of the eCB uptake/metabolism inhibitor AM404 and the phytocannabinoid cannabidiol (CBD) on the extinction of contextual fear memories in rats. Rats were conditioned and 24 h later subjected to three consecutive 9-min non-reinforced exposure...
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Published in | European neuropsychopharmacology Vol. 18; no. 12; pp. 849 - 859 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Netherlands
Elsevier B.V
01.12.2008
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Subjects | |
Online Access | Get full text |
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Summary: | Abstract The present study investigated the central effects of the eCB uptake/metabolism inhibitor AM404 and the phytocannabinoid cannabidiol (CBD) on the extinction of contextual fear memories in rats. Rats were conditioned and 24 h later subjected to three consecutive 9-min non-reinforced exposures to the conditioning context (extinction sessions, 24 h intervals). AM404 or CBD was injected i.c.v. 5 min before each extinction session and a 3-min drug-free test of contextual memory was performed 24 h after the last extinction session. AM404 (1.0 µg/µl, i.c.v.) and CBD (2.0 µg/µl, i.c.v.) facilitated extinction of contextual fear memory, with persistent effects. These responses were antagonized by the CB1-selective antagonist SR141716A (0.2 mg/kg, i.p.), but not by the TRPV1-selective antagonist capsazepine (5.0 µg/µl, i.c.v.). The effect of the anxiolytic drug Diazepam (DZP) on the extinction of contextual fear memory was also investigated. In contrast with the CBD and AM404 results, DZP induced a general reduction in the expression of conditioned freezing. Both AM404 and CBD induced anti-anxiogenic effect in the fear-potentiated plus-maze test, whereas DZP was anxiolytic in conditioned and unconditioned rats. In conclusion, CBD, a non-psychoactive phytocannabinoid could be an interesting pharmacological approach to reduce the anxiogenic effects of stress and promote the extinction of fear memories. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0924-977X 1873-7862 |
DOI: | 10.1016/j.euroneuro.2008.07.001 |