Wikipedia
muco-Inositol is a critically important chemical in the gustatory (taste) modality of the mammalian nervous system. The generic form is coupled to a phospholipid of the outer lemma of the sensory neurons associated with the sodium ion sensitive channel (previously known as the “salty” channel) of gustation.
Muco-inositol is one of nine stereo-isomers of inositol. It is the only stereo-isomer that participates in the gustatory (taste) modality.
Muco-inositol is typically phosphorylated (becoming muco-inositol phosphate) in the process of being attached to a lipid of the outer lemma of the sensory neurons of taste. The final chemical is phosphatidyl muco-inositol (PtdIns). PtdIns occurs in a specialized area of the cilia of the sensory neurons where it exists in a liquid crystalline form. In this form, it is the sensory receptor of the sensory neuron forming the initial element of the sodium ion sensitive channel of gustation.
Phosphatidyl inositol prepared in the laboratory without regard to the isomer involved is abbreviated as PI. Phosphatidyl inositol phosphate prepared without regard to the isomer involved is abbreviated as PIP.
Generic muco-inositol alone can form a dimer with the muco-inositol moiety of the sensory receptor. Although it contains no salt, or sodium ion, muco-inositol is perceived as very “salty” in this situation. It contains a natraphore within its structure.
Generic muco-inositol can also couple with the gluco-receptor of the "sweet" sensory neurons and be perceived as sweet by mammals, even though it is not a saccharide.
While classed as a sugar-alcohol for historical reasons, muco-inositol is more properly described as a sweet-alcohol due its perception by the mammal as sweet. It contains two distinct glucophores, as well as two distinct natrophores, within its aromatic structure. Aliphatic alcohols do not contain any gustaphores in their pure state and are considered tasteless. However, many impurities (more than one part per million) have been present in the aliphatic alcohols used in laboratory experiments, resulting in their having been assigned a perceptual "taste."