Kokumi Substances, Enhancers of Basic Tastes, Induce Responses in Calcium-Sensing Receptor Expressing Taste Cells

Recently, we reported that calcium-sensing receptor (CaSR) is a receptor for kokumi substances, which enhance the intensities of salty, sweet and umami tastes. Furthermore, we found that several γ-glutamyl peptides, which are CaSR agonists, are kokumi substances. In this study, we elucidated the receptor cells for kokumi substances, and their physiological properties. For this purpose, we used Calcium Green-1 loaded mouse taste cells in lingual tissue slices and confocal microscopy. Kokumi substances, applied focally around taste pores, induced an increase in the intracellular Ca2+ concentration ([Ca2+]i) in a subset of taste cells. These responses were inhibited by pretreatment with the CaSR inhibitor, NPS2143. However, the kokumi substance-induced responses did not require extracellular Ca2+. CaSR-expressing taste cells are a different subset of cells from the T1R3-expressing umami or sweet taste receptor cells. These observations indicate that CaSR-expressing taste cells are the primary detectors of kokumi substances, and that they are an independent population from the influenced basic taste receptor cells, at least in the case of sweet and umami

Ab-initio Molecular Dynamics Simulation of Li Insertion in C_<60>

Complexes composed of fullerenes and metal elements offer important examples as new nanomaterials in the field of materials design. In the collisions between C^-_ and Li^+ in plasma state, there is a possibility that the endohederal fullerene, Li@C_ is created as well as Li@C_ and so on. To study this phenomenon theoretically, we perform an all-electron mixed basis ab initio molecular dynamics simulation at 1, 000K which was developed by ourselves. When Li^+ with the kinetic energy ～5eV hits the center of a six-membered ring of C^-_, an endohedral complex, Li@C_ is created. This direcet insertion process is possible because the ionic radius of Li^+ is shorter then the radius of a six-membered ring. However, if either the kinetic energy is lower or the collision occurs off-center, the Li^+ ion stays outside and C_ is deformed by the shock

The Orientational Influence on the Electronic Structure of the Solid fcc C_<60>

The comparison of the electronic structures of fcc C_ solids between two different molecular orientations has been done by performing a band structure calculation. We have found that the molecular orientation causes considerable changes on the degeneracies at Γ points, the dispersion of bands and the location of valence band maximum and conduction band minimum. The band variation upon molecular orientation should become an important subject in physics and materials science of the new class of solid fullerenes