Sweet scent lactones activate hot capsaicin receptor, TRPV1.

In this study, we investigated the activation of Transient receptor potential vanilloid subtype 1, TRPV1, by lactones, a representative flavor ingredient currently used for foods and beverages. As a result, we found that some lactones having C4 acyl chain length, γ-octalactone, δ-nonalactone and ß-methyl-γ-octalactone, γ-undecalactone with C7 acyl chain length and δ-undecalactone with C6 acyl chain length activated TRPV1. TRPV1 is known as a non-selective cation channels that respond to a wide range of physical and chemical stimuli such as high temperature, protons, capsaicin and so on. Furthermore, it has been also demonstrated that activation of TRPV1 induced energy expenditure enhancement and thermogenesis, suppressed accumulation of visceral fat in mice and prevented non-alcoholic fatty acid liver. Thus, lactones that function as TRPV1 agonists are thought to be important candidates for decreasing the risks of developing a metabolic syndrome.

Cannabinoid in the nucleus accumbens enhances the intake of palatable solution.

It has been suggested that the activation of cannabinoid receptors in the nucleus accumbens shell facilitates feeding behavior. However, it remains unclear whether cannabinoid ligands enhance the palatability of food to facilitate feeding. In this study, we examined whether microinjecting an endogenous cannabinoid agonist, anandamide into the nucleus accumbens shell would affect the intake of water, sweet or bitter solutions. Microinjections of anandamide into the nucleus accumbens shell selectively increased the intake of saccharin (sweet) solution, but had no effect on the intake of water nor quinine (bitter) solution. These results suggest that activation of the cannabinoid receptors in the nucleus accumbens shell selectively facilitates the intake of palatable foods and solutions.