Anxiolytic-like effect induced by the cannabinoid CB1 receptor agonist, arachydonilcyclopropylamide (ACPA), in the rat amygdala is mediated through the D1 and D2 dopaminergic systems

• Published in: Journal of psychopharmacology (Oxford) 2011-01, Vol.25 (1), p.131-140
• Main Authors: Zarrindast, Mohammad Reza, Mahboobi, Sara, Sadat-Shirazi, Mitra-Sadat, Ahmadi, Shamseddin
• Format: Article
• Language: English
• Subjects: Amygdala; Amygdala - drug effects; Animals; Anti-Anxiety Agents - pharmacology; Anxiety; Anxiety - drug therapy; Anxiolytics; Apomorphine; Apomorphine - administration & dosage; Apomorphine - pharmacology; Arachidonic Acids - pharmacology; Benzazepines - administration & dosage; Benzazepines - pharmacology; Biological and medical sciences; Brain; Cannabinoid CB1 receptors; Dopamine; Dopamine D1 receptors; Dopamine D2 Receptor Antagonists; Dopamine D2 receptors; Dose-Response Relationship, Drug; Hippocampus - drug effects; Male; Medical sciences; Motor Activity - drug effects; Neuropharmacology; Pharmacology. Drug treatments; Proteins; Psycholeptics: tranquillizer, neuroleptic; Psychology. Psychoanalysis. Psychiatry; Psychopharmacology; Random Allocation; Rats; Rats, Wistar; Receptor, Cannabinoid, CB1 - agonists; Receptors, Dopamine D1 - agonists; Receptors, Dopamine D1 - antagonists & inhibitors; Receptors, Dopamine D1 - metabolism; Receptors, Dopamine D2 - agonists; Receptors, Dopamine D2 - metabolism; Rodents; Sulpiride; Sulpiride - administration & dosage; Sulpiride - pharmacology; T cell receptors
• ISSN: 0269-8811; 1461-7285
• DOI: 10.1177/0269881110376688

In the present study the influence of the dopaminergic system(s) of the amygdala on the anxiolytic-like effect of the cannabinoid CB1 receptor agonist, arachydonilcyclopropylamide (ACPA), in male Wistar rats was investigated. An elevated plus-maze test of anxiety was used to assess anxiety-like behaviors. The results showed that bilateral intra-amygdala injections of ACPA (0.125, 1.25 and 5 ng/rat) and the mixed dopamine D1/D2 receptor agonist, apomorphine, at different doses (0.001, 0.01 and 0.1 µg/rat) increased percentage open arm time (%OAT) and percentage open arm entries (%OAE), indicating an anxiolytic-like effect for both of the drugs. In contrast, intra-amygdala administration of the dopamine D1 receptor antagonist SCH23390 (0.5 and 1 µg/rat) and the dopamine D2 receptor antagonist, sulpiride (2 and 3 µg/rat) decreased %OAT and %OAE, suggesting an anxiogenic-like effect for both of the drugs. Interestingly, pretreatment with a sub-effective dose of apomorphine (0.0005 µg/rat) increased, while SCH23390 (0.25 µg/rat) and sulpiride (1.5 µg/rat) decreased the anxiolytic-like effect of ACPA. It can be concluded that the dopaminergic system of the amygdala may be involved, at least partly, in the anxiolytic-like effects induced by ACPA in the rat amygdala.