Herness M S, Gilbertson T A
College of Dentistry, Ohio State University, Columbus 43210-1241, USA.
Annu Rev Physiol. 1999;61:873-900. doi: 10.1146/annurev.physiol.61.1.873.
Taste receptor cells respond to gustatory stimuli using a complex arrangement of receptor molecules, signaling cascades, and ion channels. When stimulated, these cells produce action potentials that result in the release of neurotransmitter onto an afferent nerve fiber that in turn relays the identity and intensity of the gustatory stimuli to the brain. A variety of mechanisms are used in transducing the four primary tastes. Direct interaction of the stimuli with ion channels appears to be of particular importance in transducing stimuli reported as salty or sour, whereas the second messenger systems cyclic AMP and inositol trisphosphate are important in transducing bitter and sweet stimuli. In addition to the four basic tastes, specific mechanisms exist for the amino acid glutamate, which is sometimes termed the fifth primary taste, and for fatty acids, a so-called nonconventional taste stimulus. The emerging picture is that not only do individual taste qualities use more than one mechanism, but multiple pathways are available for individual tastants as well.
味觉感受器细胞通过受体分子、信号级联反应和离子通道的复杂排列来响应味觉刺激。受到刺激时，这些细胞会产生动作电位，导致神经递质释放到传入神经纤维上，进而将味觉刺激的特性和强度传递给大脑。在转换四种基本味觉时会用到多种机制。刺激物与离子通道的直接相互作用在转换被认为是咸或酸的刺激时似乎尤为重要，而第二信使系统环磷酸腺苷（cAMP）和肌醇三磷酸在转换苦和甜的刺激时很重要。除了四种基本味觉外，还存在针对氨基酸谷氨酸（有时被称为第五种基本味觉）和脂肪酸（一种所谓的非常规味觉刺激物）的特定机制。新出现的情况是，不仅每种味觉品质都使用不止一种机制，而且单个味觉物质也有多种途径。
