CNR2 and major depressive disorder: While these results suggest that the CB2 over-expression results in a depression-resistant endophenotype, the same study also reported that pharmacological blockade of CB2, with chronic administration of the CB2 receptor antagonist AM630 for 4 weeks, prevented the effects of CMS on tail suspension test, sucrose intake, CB2 receptor gene, BDNF gene and protein expression in wildtype mice.