کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2166088 | 1091813 | 2013 | 13 صفحه PDF | دانلود رایگان |
It is often observed in intracellular Ca2+ imaging experiments that the amplitudes of the Ca2+ signals elicited by newly characterized TRP agonists do not correlate with the amplitudes of the responses evoked subsequently by a specific potent agonist. We investigated this rather controversial phenomenon by first testing whether it is inherent to the comparison of the effects of weak and strong stimuli. Using five well-characterized TRP channel agonists in commonly used heterologous expression systems we found that the correlation between the amplitudes of the Ca2+ signals triggered by two sequentially applied stimuli is only high when both stimuli are strong. Using mathematical simulations of intracellular Ca2+ dynamics we illustrate that the innate heterogeneity in expression and functional properties of Ca2+ extrusion (e.g. plasma membrane Ca2+ ATPase) and influx (TRP channels) pathways across a cellular population is a sufficient condition for low correlation between the amplitude of Ca2+ signals elicited by weak and strong stimuli. Taken together, our data demonstrate that this phenomenon is an expected outcome of intracellular Ca2+ imaging experiments that cannot be taken as evidence for lack of specificity of low-efficacy stimuli, or as an indicator of the need of other cellular components for channel stimulation.
Journal: Cell Calcium - Volume 54, Issue 5, November 2013, Pages 362–374