These acute effects may be mediated by a variety of central loci, including the amygdala ( Fusar-Poli et al., 2009), prelimbic cortex ( Lemos et al., 2010), and bed nucleus of the stria terminalis ( Gomes et al., 2012). Acute administration of CBD decreases the expression of contextual conditioned fear memories in rats ( Resstel et al., 2006 Lemos et al., 2010 but see Marinho et al., 2015) as well as reducing physiological fear-related responses in humans ( Fusar-Poli et al., 2009). This bidirectional effect of CBD may be related to stress levels induced by conditioning and evoked at retrieval during extinction, rather than the strength of the memory per se.Ĭannabidiol (CBD) is the major non-psychotropic constituent of the Cannabis plant and has anxiolytic therapeutic potential. This pattern of results is consistent with CBD enhancing contextual fear memory extinction when the initial conditioning is strong, but impairing extinction when conditioning is weak. In contrast, when initial conditioning was weaker, CBD and MK-801 had similar effects to increase freezing at the fear retention test relative to vehicle controls, whereas DCS had no observable impact. The latter test reduction was replicated by DCS, but MK-801 instead elevated test freezing. We showed that under conditions of strong fear conditioning, CBD reduced contextual fear memory expression both acutely during the extinction session as well as later at a fear retention test.

injections of cannabidiol (10 mg/kg) with those of the NMDA receptor antagonist MK-801 (0.1 mg/kg) and partial agonist D-cycloserine (DCS 15 mg/kg) in order to determine the mnemonic basis of long-term fear reduction. Here, we directly compared the effects of i.p. The long-lasting impact might be mediated by an enhancement of memory extinction or an impairment of memory reconsolidation. 3Department of Pharmacology, University of São Paulo, São Paulo, BrazilĬannabidiol (CBD) has been established to have both acute and long-lasting effects to reduce fear memory expression.2School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, UK.1School of Psychology, University of Birmingham, Birmingham, UK.

Any-maze fear conditioning