이온통로에 의한 말초감각 신호전달 = Peripheral sensation mediated by ion channels

다국어 초록 (Multilingual Abstract)

Ion channels play various roles in our body. Here I focus on the signal transduction from the widely different modalities of external stimuli to common electrical activities such as action potential. For sensory functions of peripheral nerves, critical step is the integration of various external stimuli into a certain level of membrane potential that could be below or above `threshold voltage`. In the process of integration, both depolarizing (stimulating or pro-exciting) and hyperpolarizing (stabilizing or inhibitin) signals could be generated from ion channels that are regulated by different stimuli; temperature, mechanical stimuli (skin tactile sense and hearing), chemicals (odor, taste, pungent hazardous signal) and light (photoenergy). Recent progress in sensory physiology has elucidated precise molecular nature of the ion channels corresponding to each of the above modalities. Among hundreds of types of ion channels, the TRP (Transient Receptor Potential) superfamily shows the most intriguing properties in terms of their capability of signal transduction, and are suggested as popular targets of drug discovery to control pain and abnormal sensations. TRP channels are also found in single cell organisms and are supposed to play fundamental roles in the responses of cells to their microenvironments. Although not as popular as TRP, other types of ion channels also play critical roles in sensing physicochemical stimuli (membrane stretch, temperature and pH change). Two-pore domain K+ channels (KCNK family) and acid-sensing cation channels (ASIC) are such examples. The activation of K+ channels such as KCNK could antagonize the stimulatory influence of TRP channels. Therefore an integrative approach and interpretation is required to understand the peripheral sensation and their modulation by drugs/natural extracts based on ion channels and receptors.