NaI in PBS? - (Jun/04/2007 )

Hi all,
can anyone tell me, why is NaI added to PBS used for washing glass slides after FISH? (have this in my manual, taken from some paper), PBS is sort of standard, only NaI is needed (2,5% w/v). Can i use KI?
Thanks in advance
Michal

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as Na+ is in access, most of KI will turn to NaI;

PBS is a physiologic buffer and contains only a minor amount of K+ in order not to disturb K+-release by channels and maintenance of membrane potential; increasing K+ may have physiological effects, f.i. inhibition of K+-channels; if no living cells are treated with the buffer, you may take KI instead of NaI

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Thanks

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