A reaction-diffusion model is built to investigate the temporal and spatial patterns of cytoplasmic Ca2＋ dynamics under the effects of Ca2＋-release activated Ca2＋ （CRAC） channels in T cells. Simulation results sh...A reaction-diffusion model is built to investigate the temporal and spatial patterns of cytoplasmic Ca2＋ dynamics under the effects of Ca2＋-release activated Ca2＋ （CRAC） channels in T cells. Simulation results show a strong dependence of the modulation mode of Ca2＋ oscillation and dynamic patterns of Ca2＋ wave on the influx rate through the CRAC channel （ksoc）. When ksoc is small, cytoplasmic Ca2＋ is modulated as a frequency-modulation （FM） signal, whereas it shows an amplitude modulation （AM） mode after ksoc passes through a critical value. The heterogeneity in spatial Ca2＋ distribution is mostly arising from the influx through CRAC channels in both FM and AM modes. During each Ca2＋ spike, a more sustained cytoplasmic Ca2＋ gradient is maintained in the AM mode rather than in the FM mode.展开更多
The cytoplasmic Ca2＋ oscillations are investigated under the effect of CRAC channels in non-excitable cells （especially in T cells）. The oscillatory Ca2＋ signals can be modulated as the amplitude-, frequency- and ...The cytoplasmic Ca2＋ oscillations are investigated under the effect of CRAC channels in non-excitable cells （especially in T cells）. The oscillatory Ca2＋ signals can be modulated as the amplitude-, frequency- and mixed amplitude-frequency modulation modes dependent on the different IP3R gating models. Bifurcation analyses show that Ca2＋ signals in the single positive feedback loop model is a mixed modulation mode. In contrast, Ca2＋ signals in the Mak-McBride-Foskett model demonstrates approximately the frequency modulation mode only with slight amplitude shifts.展开更多
文摘A reaction-diffusion model is built to investigate the temporal and spatial patterns of cytoplasmic Ca2＋ dynamics under the effects of Ca2＋-release activated Ca2＋ （CRAC） channels in T cells. Simulation results show a strong dependence of the modulation mode of Ca2＋ oscillation and dynamic patterns of Ca2＋ wave on the influx rate through the CRAC channel （ksoc）. When ksoc is small, cytoplasmic Ca2＋ is modulated as a frequency-modulation （FM） signal, whereas it shows an amplitude modulation （AM） mode after ksoc passes through a critical value. The heterogeneity in spatial Ca2＋ distribution is mostly arising from the influx through CRAC channels in both FM and AM modes. During each Ca2＋ spike, a more sustained cytoplasmic Ca2＋ gradient is maintained in the AM mode rather than in the FM mode.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10834014, 10674173 and 30770517, and the National Basic Research Program of China under Grant No 2009CB930704.
文摘The cytoplasmic Ca2＋ oscillations are investigated under the effect of CRAC channels in non-excitable cells （especially in T cells）. The oscillatory Ca2＋ signals can be modulated as the amplitude-, frequency- and mixed amplitude-frequency modulation modes dependent on the different IP3R gating models. Bifurcation analyses show that Ca2＋ signals in the single positive feedback loop model is a mixed modulation mode. In contrast, Ca2＋ signals in the Mak-McBride-Foskett model demonstrates approximately the frequency modulation mode only with slight amplitude shifts.
