Abstract
Obesity is one of the major public health issues, and its prevalence is steadily increasing all the world over. The endocannabinoid system (ECS) has been shown to be involved in the intake of palatable food via activation of cannabinoid 1 receptor (CB&sub1;R). However, the involvement of lingual CB&sub1;R in the orosensory perception of dietary fatty acids has never been investigated. In the present study, behavioral tests on CB&sub1;R-/- and wild type (WT) mice showed that the invalidation of Cb&sub1;r gene was associated with low preference for solutions containing rapeseed oil or a long-chain fatty acid (LCFA), such as linoleic acid (LA). Administration of rimonabant, a CB&sub1;R inverse agonist, in mice also brought about a low preference for dietary fat. No difference in CD36 and GPR120 protein expressions were observed in taste bud cells (TBC) from WT and CB&sub1;R-/- mice. However, LCFA induced a higher increase in [Ca2+]i in TBC from WT mice than that in TBC from CB&sub1;R-/- mice. TBC from CB&sub1;R-/- mice also exhibited decreased Proglucagon and Glp-1r mRNA and a low GLP-1 basal level. We report that CB&sub1;R is involved in fat taste perception via calcium signaling and GLP-1 secretion.