ABSTRACT
BACKGROUND: Increasing the available repertoire of effective treatments for mood and anxiety disorders represents a critical unmet need. Pharmacological augmentation of endogenous cannabinoid (eCB) signaling has been suggested to represent a novel approach to the treatment of anxiety disorders; however, the functional interactions between two canonical eCB pathways mediated via anandamide (N-arachidonylethanolamine [AEA]) and 2-arachidonoylglycerol (2-AG) in the regulation of anxiety are not well understood. METHODS: We utilized pharmacological augmentation and depletion combined with behavioral and electrophysiological approaches to probe the role of 2-AG signaling in the modulation of stress-induced anxiety and the functional redundancy between AEA and 2-AG signaling in the modulation of anxiety-like behaviors in mice. RESULTS: Selective 2-AG augmentation reduced anxiety in the light/dark box assay and prevented stress-induced increases in anxiety associated with limbic AEA deficiency. In contrast, acute 2-AG depletion increased anxiety-like behaviors, which was normalized by selective pharmacological augmentation of AEA signaling and via direct cannabinoid receptor 1 stimulation with Δ9-tetrahydrocannabinol. Electrophysiological studies revealed 2-AG modulation of amygdala glutamatergic transmission as a key synaptic correlate of the anxiolytic effects of 2-AG augmentation. CONCLUSIONS: Although AEA and 2-AG likely subserve distinct physiological roles, a pharmacological and functional redundancy between these canonical eCB signaling pathways exists in the modulation of anxiety-like behaviors. These data support development of eCB-based treatment approaches for mood and anxiety disorders and suggest a potentially wider therapeutic overlap between AEA and 2-AG augmentation approaches than was previously appreciated.
Subject(s)
Anxiety/drug therapy , Arachidonic Acids/metabolism , Endocannabinoids/metabolism , Glycerides/metabolism , Signal Transduction/drug effects , Adaptation, Ocular/drug effects , Animals , Anti-Anxiety Agents/therapeutic use , Anxiety/metabolism , Anxiety/physiopathology , Benzodioxoles/therapeutic use , Brain/drug effects , Brain/metabolism , Brain/physiology , Cannabinoid Receptor Agonists/therapeutic use , Cyclohexanols/therapeutic use , Disease Models, Animal , Dronabinol/pharmacology , Excitatory Postsynaptic Potentials/drug effects , Heterocyclic Compounds, 1-Ring/therapeutic use , Locomotion/drug effects , Male , Mice , Mice, Inbred ICR , Piperidines/therapeutic use , Polyunsaturated Alkamides , Pyridines/therapeutic useABSTRACT
Studies have consistently shown that both consumption of acute amounts of alcohol and elevated antisocial psychopathic traits are associated with an impaired ability for prepotent response inhibition. This may manifest as a reduced ability to inhibit prepotent race biased responses. Here, we tested the effects of acute alcohol consumption, and elevated antisocial psychopathic traits, on judgments of the attractiveness and health of ethnic ingroup and outgroup faces. In the first study, we show that following acute alcohol consumption, at a dose that is sufficient to result in impaired performance on tests of executive function, Caucasian participants judged White faces to be more attractive and healthier compared to when sober. However, this effect did not extend to Black faces. A similar effect was found in a second study involving sober Caucasian participants where secondary psychopathic traits were related to an intergroup bias in the ratings of attractiveness for White versus Black faces. These results are discussed in terms of a model which postulates that poor prefrontal functioning leads to increases in ingroup liking as a result of impaired abilities for prepotent response inhibition.
