The peripheral cannabinoid receptor knockout mice: an update

This review gives an overview of the CB 2 receptor (CB 2 R) knockout (CB 2 R −/− ) mice phenotype and the work that has been carried out using this mutant mouse. Using the CB 2 R −/− mice, investigators have discovered the involvement of CB 2 R on immune cell function and development, infection, embryonic development, bone loss, liver disorders, pain, autoimmune inflammation, allergic dermatitis, atherosclerosis, apoptosis and chemotaxis. Using the CB 2 R −/− mice, investigators have also found that this receptor is not involved in cannabinoid‐induced hypotension. In addition, the CB 2 R −/− mice have been used to determine specific tissue CB 2 R expression. The specificity of synthetic cannabinoid agonists, antagonists and anti‐CB 2 R antibodies has been screened using tissues from CB 2 R −/− mice. Thus, the use of this mouse model has greatly helped reveal the diverse events involving the CB 2 R, and has aided in drug and antibody screening. British Journal of Pharmacology (2008) 153 , 309–318; doi: 10.1038/sj.bjp.0707527 ; published online 29 October 2007