[The endocannabinoid system and bone].

Recent studies suggest an important role for the skeletal endocannabinoid system in the regulation of bone mass in both physiological and pathological conditions. Both major endocannabinoids (anandamid and 2-arachidonoylglycerol), endocannabinoid receptors - CB1-receptor (CB1R) a CB2-receptor (CB2R) and the endocannabinoid metabolizing enzymes are present or expressed in osteoblasts and osteoclasts. Previous studies identified multiple risk and protective variants of CNR2 gene dealing with the relationship to bone density and/or osteoporosis. Selective CB1R/ CB2R-inverse agonists/antagonists and CB2R-inverse agonists/antagonists are candidates for prevention of bone mass loss and combined antiresorptive and anabolic therapy for osteoporosis.Key words: cannabinoid receptors - endocannabinoids - marijuana - osteoporosis.