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.
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.
Zarrindast
Mohammad Reza
MR
Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. zarinmr@ams.ac.ir
Mahboobi
Sara
S
Sadat-Shirazi
Mitra-Sadat
MS
Ahmadi
Shamseddin
S
D000679:Amygdala / Q000187:drug effects*; D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001007:Anxiety / Q000188:drug therapy; D001058:Apomorphine / Q000008:administration & dosage / Q000494:pharmacology; D001095:Arachidonic Acids / Q000494:pharmacology*; D001552:Benzazepines / Q000008:administration & dosage / Q000494:pharmacology; D065127:Dopamine D2 Receptor Antagonists; D004305:Dose-Response Relationship, Drug; D006624:Hippocampus / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D043884:Receptor, Cannabinoid, CB1 / Q000819:agonists*; D017447:Receptors, Dopamine D1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017448:Receptors, Dopamine D2 / Q000819:agonists / Q000378:metabolism*; D013469:Sulpiride / Q000008:administration & dosage / Q000494:pharmacology
D014151:Anti-Anxiety Agents; D001095:Arachidonic Acids; D001552:Benzazepines; D065127:Dopamine D2 Receptor Antagonists; D043884:Receptor, Cannabinoid, CB1; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; C534628:SCH 23390; C119324:arachidonylcyclopropylamide; D013469:Sulpiride; D001058:Apomorphine