E-Conference: Defining Calcium Entry Signals
18 June 2004
Indu S. AmbudkarTrevor; Point noted. I am glad you corrected me. I was actually writing within the narrow context of agonist-stimulated "store-operated" calcium entry channels.
I think your studies reveal a lot. First of all they show that different signals are generated by the same stimulus and that these signals can activate different calcium channels.
Secondly, low concentrations of agonists produce signals that activate calcium channels distinct from SOC.
The question I am trying to deal with, and what has come up in this discussion, is whether store-operated calcium entry works at these low levels of stimulii or not.
If it is seen only at higher agonist concentrations, then is it physiologically relevant (I know your answer to that one already!!!). Which is why I was trying to figure out what might be the actual agonist concentration that is sensed by the cell. After chatting with a few people, I came to the conclusion that in some cases it can be fairly high. But, of course, "in vivo" experiments will be needed to prove this. Good luck to us!!
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