“Cannabinoids are known to modulate GABAergic and glutamatergic transmission in cortical areas, the former via CB1 and the latter via a novel receptor. Pharmacological data demonstrate that several widely used cannabinoid ligands bind to both receptors, which may explain the inconsistencies in their behavioural effects.
In the present experiments, we studied the effects of the CB1 antagonist… and the cannabinoid agonist… in wild-type as well as in CB1 knockout mice… In wild types, the cannabinoid agonist… caused a decrease in anxiety-like behaviour, which was abolished by the CB1-selective antagonist…
Our studies on the behavioural effects of the cannabinoid antagonist SR-141716A and the CB1 antagonist AM-251 show that the CB1 and the novel cannabinoid receptor mediate anxiolytic (anti-anxiety) and anxiogenic (anxiety) effects, respectively.
This suggests that agonists of the former, or antagonists of the latter, are promising new compounds in the pharmacotherapy of anxiety.”