British Journal of DOI:10.1111/bph.12944 www.brjpharmacol.org BJP Pharmacology REVIEW Correspondence Dr John M McPartland, 53 Washington Street Ext., Middlebury, VT 05753, USA. Are cannabidiol and E-mail:
[email protected] 9 ---------------------------------------------------------------- Δ Received -tetrahydrocannabivarin 21 February 2014 Revised 12 September 2014 negative modulators of the Accepted endocannabinoid system? A 16 September 2014 systematic review John M McPartland1, Marnie Duncan2, Vincenzo Di Marzo3 and Roger G Pertwee4 1Division of Molecular Biology, GW Pharmaceuticals, Salisbury, Wiltshire, UK, 2GW Pharmaceuticals, Porton Down Science Park, Salisbury, Wiltshire, UK, 3Endocannabinoid Research Group, Institute of Biomolecular Chemistry, CNR, Napoli, Italy, and 4School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK Based upon evidence that the therapeutic properties of Cannabis preparations are not solely dependent upon the presence of Δ9-tetrahydrocannabinol (THC), pharmacological studies have been recently carried out with other plant cannabinoids (phytocannabinoids), particularly cannabidiol (CBD) and Δ9-tetrahydrocannabivarin (THCV). Results from some of these studies have fostered the view that CBD and THCV modulate the effects of THC via direct blockade of cannabinoid CB1 receptors, thus behaving like first-generation CB1 receptor inverse agonists, such as rimonabant. Here, we review in vitro and ex vivo mechanistic studies of CBD and THCV, and synthesize