Ultraviolet action spectrum for intracellular free Ca2+ increase in human epidermal keratinocytes.
Effects of UV on normal human epidermal keratinocytes were studied by measuring the intracellular free Ca2+ concentration ([Ca2+]i) using fluorescence ratio imaging (fura-2-AM). Upon UV irradiation the [Ca2+]i increased sharply after a certain lag time, and the UV sensitivity was higher at lower temperatures. Statistically the distribution of [Ca2+]i became broader as the mean values became larger, and the number of affected cells increased sharply above a certain fluence (light intensity x time [photons/cm2]) at all wavelengths studied (200-400 nm). The action spectrum showed a single peak at about 230 nm and decreased gradually toward longer-wavelength UV regions.
Nakagaki
T
T
Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Oda
J
J
Koizumi
H
H
Fukaya
T
T
Yasui
C
C
Ueda
T
T
D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D016257:Fura-2; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000528:radiation effects*; D011836:Radiation Tolerance; D013057:Spectrum Analysis; D013696:Temperature; D013997:Time Factors; D014466:Ultraviolet Rays
D002118:Calcium; D016257:Fura-2