CB1-independent mechanisms of Δ9-THCV, AM251 and SR141716 (rimonabant)

What is known and Objective: The potential beneficial therapeutic effects of cannabinoid CB1 receptor antagonists or partial agonists have driven drug discovery and development efforts and have led to clinical candidates. It is generally assumed that these compounds are CB1'selective' and produce their effects exclusively via CB1 receptors. Methods: A literature search was conducted of preclinical publications containing information about non-CB1 receptor pharmacology of these agents. The information was summarized and evaluated from the perspective of contribution to a fuller understanding of this aspect of these compounds. Results and Discussion: A number of recent studies have revealed that these compounds have CB1-independent pharmacological actions. We highlight the evidence regarding effects produced in cells lacking CB1 receptors, effects on neuronal membranes from CB1 receptor-deficient mutant KO 'knockout' mice and affinity for mu-opioid receptors. What is new and Conclusion: CB(1)selective antagonists and partial agonists have been studied for their anorexigenic and other potential therapeutic uses. An awareness of CB1-independent mechanism(s) of these agents might contribute to a better understanding of the pharmacologic and toxicologic profiles of these agents.