ABSTRACT
Living cells accept a wide variety of stimuli and can respond to them accurately via complex functions. Extracellular stimuli generally bind to their receptors on cellular membrane as chemical messenger molecules. Then other molecules, socalled second messengers, are introduced into intracellular space in many ways for processing information. These second messengers are recognized as key molecules that carry information in intracellular signal transduction systems. To understand how cellular information is processed, we need to see how much the second messengers are involved in living cells under various conditions. Among such second messengers, the calcium ion would be the most well understood one, because many methods [1-4], e.g., fluorescent probe [5-7], for monitoring its concentration and distribution have been developed. However, for many other organic second messengers, such as cyclic AMP (cAMP), cyclic GMP (cGMP), inositol-1,4,5-trisphosphate (IP3), cyclic ADP ribose, and alachidonic acid, convenient sensing techniques have not been established due to the difficulty of designing artificial ligands for the recognition of those second messengers. Thus, we need a novel concept to design selective ligands for such organic messengers.
